Differentiated voltage threshold metal gate structures for advanced integrated circuit structure fabrication

ABSTRACT

Embodiments of the disclosure are in the field of advanced integrated circuit structure fabrication and, in particular, 10 nanometer node and smaller integrated circuit structure fabrication and the resulting structures. In an example, an integrated circuit structure includes a fin. A gate dielectric layer is over a top of the fin and laterally adjacent sidewalls of the fin. An N-type gate electrode is over the gate dielectric layer over the top of the fin and laterally adjacent the sidewalls of the fin, the N-type gate electrode comprising a P-type metal layer on the gate dielectric layer, and an N-type metal layer on the P-type metal layer. A first N-type source or drain region is adjacent a first side of the gate electrode. A second N-type source or drain region is adjacent a second side of the gate electrode, the second side opposite the first side.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/593,149, entitled “ADVANCED INTEGRATED CIRCUIT STRUCTUREFABRICATION,” filed on Nov. 30, 2017, the entire contents of which arehereby incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the disclosure are in the field of advanced integratedcircuit structure fabrication and, in particular, 10 nanometer node andsmaller integrated circuit structure fabrication and the resultingstructures.

BACKGROUND

For the past several decades, the scaling of features in integratedcircuits has been a driving force behind an ever-growing semiconductorindustry. Scaling to smaller and smaller features enables increaseddensities of functional units on the limited real estate ofsemiconductor chips. For example, shrinking transistor size allows forthe incorporation of an increased number of memory or logic devices on achip, lending to the fabrication of products with increased capacity.The drive for ever-more capacity, however, is not without issue. Thenecessity to optimize the performance of each device becomesincreasingly significant.

Variability in conventional and currently known fabrication processesmay limit the possibility to further extend them into the 10 nanometernode or sub-10 nanometer node range. Consequently, fabrication of thefunctional components needed for future technology nodes may require theintroduction of new methodologies or the integration of new technologiesin current fabrication processes or in place of current fabricationprocesses.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a cross-sectional view of a starting structurefollowing deposition, but prior to patterning, of a hardmask materiallayer formed on an interlayer dielectric (ILD) layer.

FIG. 1B illustrates a cross-sectional view of the structure of FIG. 1Afollowing patterning of the hardmask layer by pitch halving.

FIG. 2A is a schematic of a pitch quartering approach used to fabricatesemiconductor fins, in accordance with an embodiment of the presentdisclosure.

FIG. 2B illustrates a cross-sectional view of semiconductor finsfabricated using a pitch quartering approach, in accordance with anembodiment of the present disclosure.

FIG. 3A is a schematic of a merged fin pitch quartering approach used tofabricate semiconductor fins, in accordance with an embodiment of thepresent disclosure.

FIG. 3B illustrates a cross-sectional view of semiconductor finsfabricated using a merged fin pitch quartering approach, in accordancewith an embodiment of the present disclosure.

FIGS. 4A-4C cross-sectional views representing various operations in amethod of fabricating a plurality of semiconductor fins, in accordancewith an embodiment of the present disclosure.

FIG. 5A illustrates a cross-sectional view of a pair of semiconductorfins separated by a three-layer trench isolation structure, inaccordance with an embodiment of the present disclosure.

FIG. 5B illustrates a cross-sectional view of another pair ofsemiconductor fins separated by another three-layer trench isolationstructure, in accordance with another embodiment of the presentdisclosure.

FIGS. 6A-6D illustrate a cross-sectional view of various operations inthe fabrication of a three-layer trench isolation structure, inaccordance with an embodiment of the present disclosure.

FIGS. 7A-7E illustrate angled three-dimensional cross-sectional views ofvarious operations in a method of fabricating an integrated circuitstructure, in accordance with an embodiment of the present disclosure.

FIGS. 8A-8F illustrate slightly projected cross-sectional views takenalong the a-a′ axis of FIG. 7E for various operations in a method offabricating an integrated circuit structure, in accordance with anembodiment of the present disclosure.

FIG. 9A illustrates a slightly projected cross-sectional view takenalong the a-a′ axis of FIG. 7E for an integrated circuit structureincluding permanent gate stacks and epitaxial source or drain regions,in accordance with an embodiment of the present disclosure.

FIG. 9B illustrates a cross-sectional view taken along the b-b′ axis ofFIG. 7E for an integrated circuit structure including epitaxial sourceor drain regions and a multi-layer trench isolation structure, inaccordance with an embodiment of the present disclosure.

FIG. 10 illustrates a cross-sectional view of an integrated circuitstructure taken at a source or drain location, in accordance with anembodiment of the present disclosure.

FIG. 11 illustrates a cross-sectional view of another integrated circuitstructure taken at a source or drain location, in accordance with anembodiment of the present disclosure.

FIGS. 12A-12D illustrate cross-sectional views taken at a source ordrain location and representing various operations in the fabrication ofan integrated circuit structure, in accordance with an embodiment of thepresent disclosure.

FIGS. 13A and 13B illustrate plan views representing various operationsin a method of patterning of fins with multi-gate spacing for forming alocal isolation structure, in accordance with an embodiment of thepresent disclosure.

FIGS. 14A-14D illustrate plan views representing various operations in amethod of patterning of fins with single gate spacing for forming alocal isolation structure, in accordance with another embodiment of thepresent disclosure.

FIG. 15 illustrates a cross-sectional view of an integrated circuitstructure having a fin with multi-gate spacing for local isolation, inaccordance with an embodiment of the present disclosure.

FIG. 16A illustrates a cross-sectional view of an integrated circuitstructure having a fin with single gate spacing for local isolation, inaccordance with another embodiment of the present disclosure.

FIG. 16B illustrates a cross-sectional view showing locations where afin isolation structure may be formed in place of a gate electrode, inaccordance with an embodiment of the present disclosure.

FIGS. 17A-17C illustrate various depth possibilities for a fin cutfabricated using fin trim isolation approach, in accordance with anembodiment of the preset disclosure.

FIG. 18 illustrates a plan view and corresponding cross-sectional viewtaken along the a-a′ axis showing possible options for the depth oflocal versus broader locations of fin cuts within a fin, in accordancewith an embodiment of the present disclosure.

FIGS. 19A and 19B illustrate cross-sectional views of various operationsin a method of selecting fin end stressor locations at ends of a finthat has a broad cut, in accordance with an embodiment of the presentdisclosure.

FIGS. 20A and 20B illustrate cross-sectional views of various operationsin a method of selecting fin end stressor locations at ends of a finthat has a local cut, in accordance with an embodiment of the presentdisclosure.

FIGS. 21A-21M illustrate cross-sectional views of various operation in amethod of fabricating an integrated circuit structure havingdifferentiated fin end dielectric plugs, in accordance with anembodiment of the present disclosure.

FIGS. 22A-22D illustrate cross-sectional views of exemplary structuresof a PMOS fin end stressor dielectric plug, in accordance with anembodiment of the present disclosure.

FIG. 23A illustrates a cross-sectional view of another semiconductorstructure having fin-end stress-inducing features, in accordance withanother embodiment of the present disclosure.

FIG. 23B illustrates a cross-sectional view of another semiconductorstructure having fin-end stress-inducing features, in accordance withanother embodiment of the present disclosure.

FIG. 24A illustrates an angled view of a fin having tensile uniaxialstress, in accordance with an embodiment of the present disclosure.

FIG. 24B illustrates an angled view of a fin having compressive uniaxialstress, in accordance with an embodiment of the present disclosure.

FIGS. 25A and 25B illustrate plan views representing various operationsin a method of patterning of fins with single gate spacing for forming alocal isolation structure in select gate line cut locations, inaccordance with an embodiment of the present disclosure.

FIGS. 26A-26C illustrate cross-sectional views of various possibilitiesfor dielectric plugs for poly cut and fin trim isolation (FTI) local fincut locations and poly cut only locations for various regions of thestructure of FIG. 25B, in accordance with an embodiment of the presentdisclosure.

FIG. 27A illustrates a plan view and corresponding cross-sectional viewof an integrated circuit structure having a gate line cut with adielectric plug that extends into dielectric spacers of the gate line,in accordance with an embodiment of the present disclosure.

FIG. 27B illustrates a plan view and corresponding cross-sectional viewof an integrated circuit structure having a gate line cut with adielectric plug that extends beyond dielectric spacers of the gate line,in accordance with another embodiment of the present disclosure.

FIGS. 28A-28F illustrate cross-sectional views of various operations ina method of fabricating an integrated circuit structure having a gateline cut with a dielectric plug with an upper portion that extendsbeyond dielectric spacers of the gate line and a lower portion thatextends into the dielectric spacers of the gate line, in accordance withanother embodiment of the present disclosure.

FIGS. 29A-29C illustrate a plan view and corresponding cross-sectionalviews of an integrated circuit structure having residual dummy gatematerial at portions of the bottom of a permanent gate stack, inaccordance with an embodiment of the present disclosure.

FIGS. 30A-30D illustrate cross-sectional views of various operations ina method of fabricating an integrated circuit structure having residualdummy gate material at portions of the bottom of a permanent gate stack,in accordance with another embodiment of the present disclosure.

FIG. 31A illustrates a cross-sectional view of a semiconductor devicehaving a ferroelectric or antiferroelectric gate dielectric structure,in accordance with an embodiment of the present disclosure.

FIG. 31B illustrates a cross-sectional view of another semiconductordevice having a ferroelectric or antiferroelectric gate dielectricstructure, in accordance with another embodiment of the presentdisclosure.

FIG. 32A illustrates a plan view of a plurality of gate lines over apair of semiconductor fins, in accordance with an embodiment of thepresent disclosure.

FIG. 32B illustrates a cross-sectional view, taken along the a-a′ axisof FIG. 32A, in accordance with an embodiment of the present disclosure.

FIG. 33A illustrates cross-sectional views of a pair of NMOS deviceshaving a differentiated voltage threshold based on modulated doping, anda pair of PMOS devices having a differentiated voltage threshold basedon modulated doping, in accordance with an embodiment of the presentdisclosure.

FIG. 33B illustrates cross-sectional views of a pair of NMOS deviceshaving a differentiated voltage threshold based on differentiated gateelectrode structure, and a pair of PMOS devices having a differentiatedvoltage threshold based on differentiated gate electrode structure, inaccordance with another embodiment of the present disclosure.

FIG. 34A illustrates cross-sectional views of a triplet of NMOS deviceshaving a differentiated voltage threshold based on differentiated gateelectrode structure and on modulated doping, and a triplet of PMOSdevices having a differentiated voltage threshold based ondifferentiated gate electrode structure and on modulated doping, inaccordance with an embodiment of the present disclosure.

FIG. 34B illustrates cross-sectional views of a triplet of NMOS deviceshaving a differentiated voltage threshold based on differentiated gateelectrode structure and on modulated doping, and a triplet of PMOSdevices having a differentiated voltage threshold based ondifferentiated gate electrode structure and on modulated doping, inaccordance with another embodiment of the present disclosure.

FIGS. 35A-35D illustrate cross-sectional views of various operations ina method of fabricating NMOS devices having a differentiated voltagethreshold based on differentiated gate electrode structure, inaccordance with another embodiment of the present disclosure.

FIGS. 36A-36D illustrate cross-sectional views of various operations ina method of fabricating PMOS devices having a differentiated voltagethreshold based on differentiated gate electrode structure, inaccordance with another embodiment of the present disclosure.

FIG. 37 illustrates a cross-sectional view of an integrated circuitstructure having a P/N junction, in accordance with an embodiment of thepresent disclosure.

FIGS. 38A-38H illustrate cross-sectional views of various operations ina method of fabricating an integrated circuit structure using a dualmetal gate replacement gate process flow, in accordance with anembodiment of the present disclosure.

FIGS. 39A-39H illustrate cross-sectional views representing variousoperations in a method of fabricating a dual silicide based integratedcircuit, in accordance with an embodiment of the present disclosure.

FIG. 40A illustrates a cross-sectional view of an integrated circuitstructure having trench contacts for an NMOS device, in accordance withan embodiment of the present disclosure.

FIG. 40B illustrates a cross-sectional view of an integrated circuitstructure having trench contacts for a PMOS device, in accordance withanother embodiment of the present disclosure.

FIG. 41A illustrates a cross-sectional view of a semiconductor devicehaving a conductive contact on a source or drain region, in accordancewith an embodiment of the present disclosure.

FIG. 41B illustrates a cross-sectional view of another semiconductordevice having a conductive on a raised source or drain region, inaccordance with an embodiment of the present disclosure.

FIG. 42 illustrates a plan view of a plurality of gate lines over a pairof semiconductor fins, in accordance with an embodiment of the presentdisclosure.

FIGS. 43A-43C illustrate cross-sectional views, taken along the a-a′axis of FIG. 42, for various operations in a method of fabricating anintegrated circuit structure, in accordance with an embodiment of thepresent disclosure.

FIG. 44 illustrates a cross-sectional view, taken along the b-b′ axis ofFIG. 42, for an integrated circuit structure, in accordance with anembodiment of the present disclosure.

FIGS. 45A and 45B illustrate a plan view and correspondingcross-sectional view, respectively, of an integrated circuit structureincluding trench contact plugs with a hardmask material thereon, inaccordance with an embodiment of the present disclosure.

FIGS. 46A-46D illustrate cross-sectional views representing variousoperations in a method of fabricating an integrated circuit structureincluding trench contact plugs with a hardmask material thereon, inaccordance with an embodiment of the present disclosure.

FIG. 47A illustrates a plan view of a semiconductor device having a gatecontact disposed over an inactive portion of a gate electrode. FIG. 47Billustrates a cross-sectional view of a non-planar semiconductor devicehaving a gate contact disposed over an inactive portion of a gateelectrode.

FIG. 48A illustrates a plan view of a semiconductor device having a gatecontact via disposed over an active portion of a gate electrode, inaccordance with an embodiment of the present disclosure. FIG. 48Billustrates a cross-sectional view of a non-planar semiconductor devicehaving a gate contact via disposed over an active portion of a gateelectrode, in accordance with an embodiment of the present disclosure.

FIGS. 49A-49D illustrate cross-sectional views representing variousoperations in a method of fabricating a semiconductor structure having agate contact structure disposed over an active portion of a gate, inaccordance with an embodiment of the present disclosure.

FIG. 50 illustrates a plan view and corresponding cross-sectional viewsof an integrated circuit structure having trench contacts including anoverlying insulating cap layer, in accordance with an embodiment of thepresent disclosure.

FIGS. 51A-51F illustrate cross-sectional views of various integratedcircuit structures, each having trench contacts including an overlyinginsulating cap layer and having gate stacks including an overlyinginsulating cap layer, in accordance with an embodiment of the presentdisclosure.

FIG. 52A illustrates a plan view of another semiconductor device havinga gate contact via disposed over an active portion of a gate, inaccordance with another embodiment of the present disclosure.

FIG. 52B illustrates a plan view of another semiconductor device havinga trench contact via coupling a pair of trench contacts, in accordancewith another embodiment of the present disclosure.

FIGS. 53A-53E illustrate cross-sectional views representing variousoperations in a method of fabricating an integrated circuit structurewith a gate stack having an overlying insulating cap layer, inaccordance with an embodiment of the present disclosure.

FIG. 54 is a schematic of a pitch quartering approach used to fabricatetrenches for interconnect structures, in accordance with an embodimentof the present disclosure.

FIG. 55A illustrates a cross-sectional view of a metallization layerfabricated using pitch quartering scheme, in accordance with anembodiment of the present disclosure.

FIG. 55B illustrates a cross-sectional view of a metallization layerfabricated using pitch halving scheme above a metallization layerfabricated using pitch quartering scheme, in accordance with anembodiment of the present disclosure.

FIG. 56A illustrates a cross-sectional view of an integrated circuitstructure having a metallization layer with a metal line compositionabove a metallization layer with a differing metal line composition, inaccordance with an embodiment of the present disclosure.

FIG. 56B illustrates a cross-sectional view of an integrated circuitstructure having a metallization layer with a metal line compositioncoupled to a metallization layer with a differing metal linecomposition, in accordance with an embodiment of the present disclosure.

FIGS. 57A-57C illustrate cross-section views of individual interconnectlines having various liner and conductive capping structuralarrangements, in accordance with an embodiment of the presentdisclosure.

FIG. 58 illustrates a cross-sectional view of an integrated circuitstructure having four metallization layers with a metal line compositionand pitch above two metallization layers with a differing metal linecomposition and smaller pitch, in accordance with an embodiment of thepresent disclosure.

FIGS. 59A-59D illustrate cross-section views of various interconnectline ad via arrangements having a bottom conductive layer, in accordancewith an embodiment of the present disclosure.

FIGS. 60A-60D illustrate cross-sectional views of structuralarrangements for a recessed line topography of a BEOL metallizationlayer, in accordance with an embodiment of the present disclosure.

FIGS. 61A-61D illustrate cross-sectional views of structuralarrangements for a stepped line topography of a BEOL metallizationlayer, in accordance with an embodiment of the present disclosure.

FIG. 62A illustrates a plan view and corresponding cross-sectional viewtaken along the a-a′ axis of the plan view of a metallization layer, inaccordance with an embodiment of the present disclosure.

FIG. 62B illustrates a cross-sectional view of a line end or plug, inaccordance with an embodiment of the present disclosure.

FIG. 62C illustrates another cross-sectional view of a line end or plug,in accordance with an embodiment of the present disclosure.

FIGS. 63A-63F illustrate plan views and corresponding cross-sectionalviews representing various operations in a plug last processing scheme,in accordance with an embodiment of the present disclosure.

FIG. 64A illustrates a cross-sectional view of a conductive line plughaving a seam therein, in accordance with an embodiment of the presentdisclosure.

FIG. 64B illustrates a cross-sectional view of a stack of metallizationlayers including a conductive line plug at a lower metal line location,in accordance with an embodiment of the present disclosure.

FIG. 65 illustrates a first view of a cell layout for a memory cell.

FIG. 66 illustrates a first view of a cell layout for a memory cellhaving an internal node jumper, in accordance with an embodiment of thepresent disclosure.

FIG. 67 illustrates a second view of a cell layout for a memory cell.

FIG. 68 illustrates a second view of a cell layout for a memory cellhaving an internal node jumper, in accordance with an embodiment of thepresent disclosure.

FIG. 69 illustrates a third view of a cell layout for a memory cell.

FIG. 70 illustrates a third view of a cell layout for a memory cellhaving an internal node jumper, in accordance with an embodiment of thepresent disclosure.

FIGS. 71A and 71B illustrate a bit cell layout and a schematic diagram,respectively, for a six transistor (6T) static random access memory(SRAM), in accordance with an embodiment of the present disclosure.

FIG. 72 illustrates cross-sectional views of two different layouts for asame standard cell, in accordance with an embodiment of the presentdisclosure.

FIG. 73 illustrates plan views of four different cell arrangementsindicating the even (E) or odd (O) designation, in accordance with anembodiment of the present disclosure.

FIG. 74 illustrates a plan view of a block level poly grid, inaccordance with an embodiment of the present disclosure.

FIG. 75 illustrates an exemplary acceptable (pass) layout based onstandard cells having different versions, in accordance with anembodiment of the present disclosure.

FIG. 76 illustrates an exemplary unacceptable (fail) layout based onstandard cells having different versions, in accordance with anembodiment of the present disclosure.

FIG. 77 illustrates another exemplary acceptable (pass) layout based onstandard cells having different versions, in accordance with anembodiment of the present disclosure.

FIG. 78 illustrates a partially cut plan view and a correspondingcross-sectional view of a fin-based thin film resistor structure, wherethe cross-sectional view is taken along the a-a′ axis of the partiallycut plan view, in accordance with an embodiment of the presentdisclosure.

FIGS. 79-83 illustrate plan views and corresponding cross-sectional viewrepresenting various operations in a method of fabricating a fin-basedthin film resistor structure, in accordance with an embodiment of thepresent disclosure.

FIG. 84 illustrates a plan view of a fin-based thin film resistorstructure with a variety of exemplary locations for anode or cathodeelectrode contacts, in accordance with an embodiment of the presentdisclosure.

FIGS. 85A-85D illustrate plan views of various fin geometries forfabricating a fin-based precision resistor, in accordance with anembodiment of the present disclosure.

FIG. 86 illustrates a cross sectional view of a lithography maskstructure, in accordance with an embodiment of the present disclosure.

FIG. 87 illustrates a computing device in accordance with oneimplementation of the disclosure.

FIG. 88 illustrates an interposer that includes one or more embodimentsof the disclosure.

FIG. 89 is an isometric view of a mobile computing platform employing anIC fabricated according to one or more processes described herein orincluding one or more features described herein, in accordance with anembodiment of the present disclosure.

FIG. 90 illustrates a cross-sectional view of a flip-chip mounted die,in accordance with an embodiment of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

Advanced integrated circuit structure fabrication is described. In thefollowing description, numerous specific details are set forth, such asspecific integration and material regimes, in order to provide athorough understanding of embodiments of the present disclosure. It willbe apparent to one skilled in the art that embodiments of the presentdisclosure may be practiced without these specific details. In otherinstances, well-known features, such as integrated circuit designlayouts, are not described in detail in order to not unnecessarilyobscure embodiments of the present disclosure. Furthermore, it is to beappreciated that the various embodiments shown in the Figures areillustrative representations and are not necessarily drawn to scale.

The following detailed description is merely illustrative in nature andis not intended to limit the embodiments of the subject matter or theapplication and uses of such embodiments. As used herein, the word“exemplary” means “serving as an example, instance, or illustration.”Any implementation described herein as exemplary is not necessarily tobe construed as preferred or advantageous over other implementations.Furthermore, there is no intention to be bound by any expressed orimplied theory presented in the preceding technical field, background,brief summary or the following detailed description.

This specification includes references to “one embodiment” or “anembodiment.” The appearances of the phrases “in one embodiment” or “inan embodiment” do not necessarily refer to the same embodiment.Particular features, structures, or characteristics may be combined inany suitable manner consistent with this disclosure.

Terminology. The following paragraphs provide definitions or context forterms found in this disclosure (including the appended claims):

“Comprising.” This term is open-ended. As used in the appended claims,this term does not foreclose additional structure or operations.

“Configured To.” Various units or components may be described or claimedas “configured to” perform a task or tasks. In such contexts,“configured to” is used to connote structure by indicating that theunits or components include structure that performs those task or tasksduring operation. As such, the unit or component can be said to beconfigured to perform the task even when the specified unit or componentis not currently operational (e.g., is not on or active). Reciting thata unit or circuit or component is “configured to” perform one or moretasks is expressly intended not to invoke 35 U.S.C. § 112, sixthparagraph, for that unit or component.

“First,” “Second,” etc. As used herein, these terms are used as labelsfor nouns that they precede, and do not imply any type of ordering(e.g., spatial, temporal, logical, etc.).

“Coupled”—The following description refers to elements or nodes orfeatures being “coupled” together. As used herein, unless expresslystated otherwise, “coupled” means that one element or node or feature isdirectly or indirectly joined to (or directly or indirectly communicateswith) another element or node or feature, and not necessarilymechanically.

In addition, certain terminology may also be used in the followingdescription for the purpose of reference only, and thus are not intendedto be limiting. For example, terms such as “upper”, “lower”, “above”,and “below” refer to directions in the drawings to which reference ismade. Terms such as “front”, “back”, “rear”, “side”, “outboard”, and“inboard” describe the orientation or location or both of portions ofthe component within a consistent but arbitrary frame of reference whichis made clear by reference to the text and the associated drawingsdescribing the component under discussion. Such terminology may includethe words specifically mentioned above, derivatives thereof, and wordsof similar import.

“Inhibit”—As used herein, inhibit is used to describe a reducing orminimizing effect. When a component or feature is described asinhibiting an action, motion, or condition it may completely prevent theresult or outcome or future state completely. Additionally, “inhibit”can also refer to a reduction or lessening of the outcome, performance,or effect which might otherwise occur. Accordingly, when a component,element, or feature is referred to as inhibiting a result or state, itneed not completely prevent or eliminate the result or state.

Embodiments described herein may be directed to front-end-of-line (FEOL)semiconductor processing and structures. FEOL is the first portion ofintegrated circuit (IC) fabrication where the individual devices (e.g.,transistors, capacitors, resistors, etc.) are patterned in thesemiconductor substrate or layer. FEOL generally covers everything up to(but not including) the deposition of metal interconnect layers.Following the last FEOL operation, the result is typically a wafer withisolated transistors (e.g., without any wires).

Embodiments described herein may be directed to back end of line (BEOL)semiconductor processing and structures. BEOL is the second portion ofIC fabrication where the individual devices (e.g., transistors,capacitors, resistors, etc.) get interconnected with wiring on thewafer, e.g., the metallization layer or layers. BEOL includes contacts,insulating layers (dielectrics), metal levels, and bonding sites forchip-to-package connections. In the BEOL part of the fabrication stagecontacts (pads), interconnect wires, vias and dielectric structures areformed. For modern IC processes, more than 10 metal layers may be addedin the BEOL.

Embodiments described below may be applicable to FEOL processing andstructures, BEOL processing and structures, or both FEOL and BEOLprocessing and structures. In particular, although an exemplaryprocessing scheme may be illustrated using a FEOL processing scenario,such approaches may also be applicable to BEOL processing. Likewise,although an exemplary processing scheme may be illustrated using a BEOLprocessing scenario, such approaches may also be applicable to FEOLprocessing.

Pitch division processing and patterning schemes may be implemented toenable embodiments described herein or may be included as part ofembodiments described herein. Pitch division patterning typically refersto pitch halving, pitch quartering etc. Pitch division schemes may beapplicable to FEOL processing, BEOL processing, or both FEOL (device)and BEOL (metallization) processing. In accordance with one or moreembodiments described herein, optical lithography is first implementedto print unidirectional lines (e.g., either strictly unidirectional orpredominantly unidirectional) in a pre-defined pitch. Pitch divisionprocessing is then implemented as a technique to increase line density.

In an embodiment, the term “grating structure” for fins, gate lines,metal lines, ILD lines or hardmask lines is used herein to refer to atight pitch grating structure. In one such embodiment, the tight pitchis not achievable directly through a selected lithography. For example,a pattern based on a selected lithography may first be formed, but thepitch may be halved by the use of spacer mask patterning, as is known inthe art. Even further, the original pitch may be quartered by a secondround of spacer mask patterning. Accordingly, the grating-like patternsdescribed herein may have metal lines, ILD lines or hardmask linesspaced at a substantially consistent pitch and having a substantiallyconsistent width. For example, in some embodiments the pitch variationwould be within ten percent and the width variation would be within tenpercent, and in some embodiments, the pitch variation would be withinfive percent and the width variation would be within five percent. Thepattern may be fabricated by a pitch halving or pitch quartering, orother pitch division, approach. In an embodiment, the grating is notnecessarily single pitch.

In a first example, pitch halving can be implemented to double the linedensity of a fabricated grating structure. FIG. 1A illustrates across-sectional view of a starting structure following deposition, butprior to patterning, of a hardmask material layer formed on aninterlayer dielectric (ILD) layer. FIG. 1B illustrates a cross-sectionalview of the structure of FIG. 1A following patterning of the hardmasklayer by pitch halving.

Referring to FIG. 1A, a starting structure 100 has a hardmask materiallayer 104 formed on an interlayer dielectric (ILD) layer 102. Apatterned mask 106 is disposed above the hardmask material layer 104.The patterned mask 106 has spacers 108 formed along sidewalls offeatures (lines) thereof, on the hardmask material layer 104.

Referring to FIG. 1B, the hardmask material layer 104 is patterned in apitch halving approach. Specifically, the patterned mask 106 is firstremoved. The resulting pattern of the spacers 108 has double thedensity, or half the pitch or the features of the mask 106. The patternof the spacers 108 is transferred, e.g., by an etch process, to thehardmask material layer 104 to form a patterned hardmask 110, as isdepicted in FIG. 1B. In one such embodiment, the patterned hardmask 110is formed with a grating pattern having unidirectional lines. Thegrating pattern of the patterned hardmask 110 may be a tight pitchgrating structure. For example, the tight pitch may not be achievabledirectly through selected lithography techniques. Even further, althoughnot shown, the original pitch may be quartered by a second round ofspacer mask patterning. Accordingly, the grating-like pattern of thepatterned hardmask 110 of FIG. 1B may have hardmask lines spaced at aconstant pitch and having a constant width relative to one another. Thedimensions achieved may be far smaller than the critical dimension ofthe lithographic technique employed.

Accordingly, for either front-end of line (FEOL) or back-end of line(BEOL), or both, integrations schemes, a blanket film may be patternedusing lithography and etch processing which may involve, e.g.,spacer-based-double-patterning (SBDP) or pitch halving, orspacer-based-quadruple-patterning (SBQP) or pitch quartering. It is tobe appreciated that other pitch division approaches may also beimplemented. In any case, in an embodiment, a gridded layout may befabricated by a selected lithography approach, such as 193 nm immersionlithography (193i). Pitch division may be implemented to increase thedensity of lines in the gridded layout by a factor of n. Gridded layoutformation with 193i lithography plus pitch division by a factor of ‘n’can be designated as 193i+P/n Pitch Division. In one such embodiment,193 nm immersion scaling can be extended for many generations with costeffective pitch division.

In the manufacture of integrated circuit devices, multi-gatetransistors, such as tri-gate transistors, have become more prevalent asdevice dimensions continue to scale down. Tri-gate transistors aregenerally fabricated on either bulk silicon substrates orsilicon-on-insulator substrates. In some instances, bulk siliconsubstrates are preferred due to their lower cost and compatibility withthe existing high-yielding bulk silicon substrate infrastructure.

Scaling multi-gate transistors has not been without consequence,however. As the dimensions of these fundamental building blocks ofmicroelectronic circuitry are reduced and as the sheer number offundamental building blocks fabricated in a given region is increased,the constraints on the semiconductor processes used to fabricate thesebuilding blocks have become overwhelming.

In accordance with one or more embodiments of the present disclosure, apitch quartering approach is implemented for patterning a semiconductorlayer to form semiconductor fins. In one or more embodiments, a mergedfin pitch quartering approach is implemented.

FIG. 2A is a schematic of a pitch quartering approach 200 used tofabricate semiconductor fins, in accordance with an embodiment of thepresent disclosure. FIG. 2B illustrates a cross-sectional view ofsemiconductor fins fabricated using a pitch quartering approach, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 2A, at operation (a), a photoresist layer (PR) ispatterned to form photoresist features 202. The photoresist features 202may be patterned using standard lithographic processing techniques, suchas 193 immersion lithography. At operation (b), the photoresist features202 are used to pattern a material layer, such as an insulating ordielectric hardmask layer, to form first backbone (BB1) features 204.First spacer (SP1) features 206 are then formed adjacent the sidewallsof the first backbone features 204. At operation (c), the first backbonefeatures 204 are removed to leave only the first spacer features 206remaining. Prior to or during the removal of the first backbone features204, the first spacer features 206 may be thinned to form thinned firstspacer features 206′, as is depicted in FIG. 2A. This thinning can beperformed prior to (as depicted) of after BB1 (feature 204) removal,depending on the required spacing and sizing needed for the BB2 features(208, described below). At operation (d), the first spacer features 206or the thinned first spacer features 206′ are used to pattern a materiallayer, such as an insulating or dielectric hardmask layer, to formsecond backbone (BB2) features 208. Second spacer (SP2) features 210 arethen formed adjacent the sidewalls of the second backbone features 208.At operation (e), the second backbone features 208 are removed to leaveonly the second spacer features 210 remaining. The remaining secondspacer features 210 may then be used to pattern a semiconductor layer toprovide a plurality of semiconductor fins having a pitch quartereddimension relative to the initial patterned photoresist features 202. Asan example, referring to FIG. 2B, a plurality of semiconductor fins 250,such as silicon fins formed from a bulk silicon layer, is formed usingthe second spacer features 210 as a mask for the patterning, e.g., a dryor plasma etch patterning. In the example of FIG. 2B, the plurality ofsemiconductor fins 250 has essentially a same pitch and spacingthroughout.

It is to be appreciated that the spacing between initially patternedphotoresist features can be modified to vary the structural result ofthe pitch quartering process. In an example, FIG. 3A is a schematic of amerged fin pitch quartering approach 300 used to fabricate semiconductorfins, in accordance with an embodiment of the present disclosure. FIG.3B illustrates a cross-sectional view of semiconductor fins fabricatedusing a merged fin pitch quartering approach, in accordance with anembodiment of the present disclosure.

Referring to FIG. 3A, at operation (a), a photoresist layer (PR) ispatterned to form photoresist features 302. The photoresist features 302may be patterned using standard lithographic processing techniques, suchas 193 immersion lithography, but at a spacing that may ultimatelyinterfere with design rules required to produce a uniform pitchmultiplied pattern (e.g., a spacing referred to as a sub design rulespace). At operation (b), the photoresist features 302 are used topattern a material layer, such as an insulating or dielectric hardmasklayer, to form first backbone (BB1) features 304. First spacer (SP1)features 306 are then formed adjacent the sidewalls of the firstbackbone features 304. However, in contrast to the scheme illustrated inFIG. 2A, some of the adjacent first spacer features 306 are mergedspacer features as a result of the tighter photoresist features 302. Atoperation (c), the first backbone features 304 are removed to leave onlythe first spacer features 306 remaining. Prior to or after the removalof the first backbone features 304, some of the first spacer features306 may be thinned to form thinned first spacer features 306′, as isdepicted in FIG. 3A. At operation (d), the first spacer features 306 andthe thinned first spacer features 306′ are used to pattern a materiallayer, such as an insulating or dielectric hardmask layer, to formsecond backbone (BB2) features 308. Second spacer (SP2) features 310 arethen formed adjacent the sidewalls of the second backbone features 308.However, in locations where BB2 features 308 are merged features, suchas at the central BB2 features 308 of FIG. 3A, second spacers are notformed. At operation (e), the second backbone features 308 are removedto leave only the second spacer features 310 remaining. The remainingsecond spacer features 310 may then be used to pattern a semiconductorlayer to provide a plurality of semiconductor fins having a pitchquartered dimension relative to the initial patterned photoresistfeatures 302.

As an example, referring to FIG. 3B, a plurality of semiconductor fins350, such as silicon fins formed from a bulk silicon layer, is formedusing the second spacer features 310 as a mask for the patterning, e.g.,a dry or plasma etch patterning. In the example of FIG. 3B, however, theplurality of semiconductor fins 350 has a varied pitch and spacing. Sucha merged fin spacer patterning approach may be implemented toessentially eliminate the presence of a fin in certain locations of apattern of a plurality of fins. Accordingly, merging the first spacerfeatures 306 in certain locations allows for the fabrication of six orfour fins with based on two first backbone features 304, which typicallygenerate eight fins, as described in association with FIGS. 2A and 2B.In one example, in board fins have a tighter pitch than would normallybe allowed by creating the fins at uniform pitch and then cutting theunneeded fins, although the latter approach may still be implemented inaccordance with embodiments described herein.

In an exemplary embodiment, referring to FIG. 3B, an integrated circuitstructure, a first plurality of semiconductor fins 352 has a longestdimension along a first direction (y, into the page). Adjacentindividual semiconductor fins 353 of the first plurality ofsemiconductor fins 352 are spaced apart from one another by a firstamount (S11) in a second direction (x) orthogonal to the first directiony. A second plurality of semiconductor fins 354 has a longest dimensionalong the first direction y. Adjacent individual semiconductor fins 355of the second plurality of semiconductor fins 354 are spaced apart fromone another by the first amount (S1) in the second direction. Closestsemiconductor fins 356 and 357 of the first plurality of semiconductorfins 352 and the second plurality of semiconductor fins 354,respectively, are spaced apart from one another by a second amount (S2)in the second direction x. In an embodiment, the second amount S2 isgreater than the first amount S1 but less than twice the first amountS1. In another embodiment, the second amount S2 is more than two timesthe first amount S1.

In one embodiment, the first plurality of semiconductor fins 352 and thesecond plurality of semiconductor fins 354 include silicon. In oneembodiment, the first plurality of semiconductor fins 352 and the secondplurality of semiconductor fins 354 are continuous with an underlyingmonocrystalline silicon substrate. In one embodiment, individual ones ofthe first plurality of semiconductor fins 352 and the second pluralityof semiconductor fins 354 have outwardly tapering sidewalls along thesecond direction x from a top to a bottom of individual ones of thefirst plurality of semiconductor fins 352 and the second plurality ofsemiconductor fins 354. In one embodiment, the first plurality ofsemiconductor fins 352 has exactly five semiconductor fins, and thesecond plurality of semiconductor fins 354 has exactly fivesemiconductor fins.

In another exemplary embodiment, referring to FIGS. 3A and 3B, a methodof fabricating an integrated circuit structure includes forming a firstprimary backbone structure 304 (left BB1) and a second primary backbonestructure 304 (right BB1). Primary spacer structures 306 are formedadjacent sidewalls of the first primary backbone structure 304 (leftBB1) and the second primary backbone structure 304 (right BB1) Primaryspacer structures 306 between the first primary backbone structure 304(left BB1) and the second primary backbone structure 304 (right BB1) aremerged. The first primary backbone structure (left BB1) and the secondprimary backbone structure (right BB1) are removed, and first, second,third and fourth secondary backbone structures 308 are provided. Thesecond and third secondary backbone structures (e.g., the central pairof the secondary backbone structures 308) are merged. Secondary spacerstructures 310 are formed adjacent sidewalls of the first, second, thirdand fourth secondary backbone structures 308. The first, second, thirdand fourth secondary backbone structures 308 are then removed. Asemiconductor material is then patterned with the secondary spacerstructures 310 to form semiconductor fins 350 in the semiconductormaterial.

In one embodiment, the first primary backbone structure 304 (left BB1)and the second primary backbone structure 304 (right BB1) are patternedwith a sub-design rule spacing between the first primary backbonestructure and the second primary backbone structure. In one embodiment,the semiconductor material includes silicon. In one embodiment,individual ones of the semiconductor fins 350 have outwardly taperingsidewalls along the second direction x from a top to a bottom ofindividual ones of the semiconductor fins 350. In one embodiment, thesemiconductor fins 350 are continuous with an underlying monocrystallinesilicon substrate. In one embodiment, patterning the semiconductormaterial with the secondary spacer structures 310 includes forming afirst plurality of semiconductor fins 352 having a longest dimensionalong a first direction y, where adjacent individual semiconductor finsof the first plurality of semiconductor fins 352 are spaced apart fromone another by a first amount S1 in a second direction x orthogonal tothe first direction y. A second plurality of semiconductor fins 354 isformed having a longest dimension along the first direction y, whereadjacent individual semiconductor fins of the second plurality ofsemiconductor fins 354 are spaced apart from one another by the firstamount S1 in the second direction x. Closest semiconductor fins 356 and357 of the first plurality of semiconductor fins 352 and the secondplurality of semiconductor fins 354, respectively, are spaced apart fromone another by a second amount S2 in the second direction x. In anembodiment, the second amount S2 is greater than the first amount S1. Inone such embodiment, the second amount S2 is less than twice the firstamount S1. In another such embodiment, the second amount S2 is more thantwo times but less than three times greater than the first amount S1. Inan embodiment, the first plurality of semiconductor fins 352 has exactlyfive semiconductor fins, and the second plurality of semiconductor fins254 has exactly five semiconductor fins, as is depicted in FIG. 3B.

In another aspect, it is to be appreciated that a fin trim process,where fin removal is performed as an alternative to a merged finapproach, fins may be trimmed (removed) during hardmask patterning or byphysically removing the fin. As an example, of the latter approach,FIGS. 4A-4C cross-sectional views representing various operations in amethod of fabricating a plurality of semiconductor fins, in accordancewith an embodiment of the present disclosure.

Referring to FIG. 4A, a patterned hardmask layer 402 is formed above asemiconductor layer 404, such as a bulk single crystalline siliconlayer. Referring to FIG. 4B, fins 406 are then formed in thesemiconductor layer 404, e.g., by a dry or plasma etch process.Referring to FIG. 4C, select fins 406 are removed, e.g., using a maskingand etch process. In the example shown, one of the fins 406 is removedand may leave a remnant fin stub 408, as is depicted in FIG. 4C. In sucha “fin trim last” approach, the hardmask 402 is patterned as whole toprovide a grating structure without removal or modification ofindividual features. The fin population is not modified until after finsare fabricated.

In another aspect, a multi-layer trench isolation region, which may bereferred to as a shallow trench isolation (STI) structure, may beimplemented between semiconductor fins. In an embodiment, a multi-layerSTI structure is formed between silicon fins formed in a bulk siliconsubstrate to define sub-fin regions of the silicon fins.

It may be desirable to use bulk silicon for fins or trigate basedtransistors. However, there is a concern that regions (sub-fin) belowthe active silicon fin portion of the device (e.g., the gate-controlledregion, or HSi) is under diminished or no gate control. As such, ifsource or drain regions are at or below the HSi point, then leakagepathways may exist through the sub-fin region. It may be the case thatleakage pathways in the sub-fin region should be controlled for properdevice operation.

One approach to addressing the above issues have involved the use ofwell implant operations, where the sub-fin region is heavily doped(e.g., much greater than 2E18/cm³), which shuts off sub-fin leakage butleads to substantial doping in the fin as well. The addition of haloimplants further increases fin doping such that end of line fins aredoped at a high level (e.g., greater than approximately 1E18/cm³).

Another approach involves doping provided through sub-fin doping withoutnecessarily delivering the same level of doping to the HSi portions ofthe fins. Processes may involve selectively doping sub-fin regions oftri-gate or FinFET transistors fabricated on bulk silicon wafers, e.g.,by way of tri-gate doped glass sub-fin out-diffusion. For example,selectively doping a sub-fin region of tri-gate or FinFET transistorsmay mitigate sub-fin leakage while simultaneously keeping fin dopinglow. Incorporation of a solid state doping sources (e.g., p-type andn-type doped oxides, nitrides, or carbides) into the transistor processflow, which after being recessed from the fin sidewalls, delivers welldoping into the sub-fin region while keeping the fin body relativelyundoped.

Thus, process schemes may include the use of a solid source doping layer(e.g. boron doped oxide) deposited on fins subsequent to fin etch.Later, after trench fill and polish, the doping layer is recessed alongwith the trench fill material to define the fin height (HSi) for thedevice. The operation removes the doping layer from the fin sidewallsabove HSi. Therefore, the doping layer is present only along the finsidewalls in the sub-fin region which ensures precise control of dopingplacement. After a drive-in anneal, high doping is limited to thesub-fin region, quickly transitioning to low doping in the adjacentregion of the fin above HSi (which forms the channel region of thetransistor). In general, borosilicate glass (BSG) is implemented forNMOS fin doping, while a phosphosilicate (PSG) or arsenic-silicate glass(AsSG) layer is implemented for PMOS fin doping. In one example, such aP-type solid state dopant source layer is a BSG layer having a boronconcentration approximately in the range of 0.1-10 weight %. In aanother example, such an N-type solid state dopant source layer is a PSGlayer or an AsSG layer having a phosphorous or arsenic, respectively,concentration approximately in the range of 0.1-10 weight %. A siliconnitride capping layer may be included on the doping layer, and a silicondioxide or silicon oxide fill material may then be included on thesilicon nitride capping layer.

In accordance with another embodiment of the present disclosure, sub finleakage is sufficiently low for relatively thinner fins (e.g., finshaving a width of less than approximately 20 nanometers) where anundoped or lightly doped silicon oxide or silicon dioxide film is formeddirectly adjacent a fin, a silicon nitride layer is formed on theundoped or lightly doped silicon oxide or silicon dioxide film, and asilicon dioxide or silicon oxide fill material is included on thesilicon nitride capping layer. It is to be appreciated that doping, suchas halo doping, of the sub-fin regions may also be implemented with sucha structure.

FIG. 5A illustrates a cross-sectional view of a pair of semiconductorfins separated by a three-layer trench isolation structure, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 5A, an integrated circuit structure includes a fin502, such as a silicon fin. The fin 502 has a lower fin portion(sub-fin) 502A and an upper fin portion 502B (Hsi). A first insulatinglayer 504 is directly on sidewalls of the lower fin portion 502A of thefin 502. A second insulating layer 506 is directly on the firstinsulating layer 504 directly on the sidewalls of the lower fin portion502A of the fin 502. A dielectric fill material 508 is directlylaterally adjacent to the second insulating layer 506 directly on thefirst insulating layer 504 directly on the sidewalls of the lower finportion 502A of the fin 502.

In an embodiment, the first insulating layer 504 is a non-dopedinsulating layer including silicon and oxygen, such as a silicon oxideor silicon dioxide insulating layer. In an embodiment, the firstinsulating layer 504 includes silicon and oxygen and has no other atomicspecies having an atomic concentration greater than 1E15 atoms per cubiccentimeter. In an embodiment, the first insulating layer 504 has athickness in the range of 0.5-2 nanometers.

In an embodiment, the second insulating layer 506 includes silicon andnitrogen, such as a stoichiometric Si₃N₄ silicon nitride insulatinglayer, a silicon-rich silicon nitride insulating layer, or asilicon-poor silicon nitride insulating layer. In an embodiment, thesecond insulating layer 506 has a thickness in the range of 2-5nanometers.

In an embodiment, the dielectric fill material 508 includes silicon andoxygen, such as a silicon oxide or silicon dioxide insulating layer. Inan embodiment, a gate electrode is ultimately formed over a top of andlaterally adjacent to sidewalls of the upper fin portion 502B of the fin502.

It is to be appreciated that during processing, upper fin portions ofsemiconductor fins may be eroded or consumed. Also, trench isolationstructures between fins may also become eroded to have non-planartopography or may be formed with non-planar topography up fabrication.As an example, FIG. 5B illustrates a cross-sectional view of anotherpair of semiconductor fins separated by another three-layer trenchisolation structure, in accordance with another embodiment of thepresent disclosure.

Referring to FIG. 5B, an integrated circuit structure includes a firstfin 552, such as a silicon fin. The first fin 552 has a lower finportion 552A and an upper fin portion 552B and a shoulder feature 554 ata region between the lower fin portion 552A and the upper fin portion552B. A second fin 562, such as a second silicon fin, has a lower finportion 562A and an upper fin portion 562B and a shoulder feature 564 ata region between the lower fin portion 562A and the upper fin portion562B. A first insulating layer 574 is directly on sidewalls of the lowerfin portion 552A of the first fin 552 and directly on sidewalls of thelower fin portion 562A of the second fin 562. The first insulating layer574 has a first end portion 574A substantially co-planar with theshoulder feature 554 of the first fin 552, and the first insulatinglayer 574 further has a second end portion 574B substantially co-planarwith the shoulder feature 564 of the second fin 562. A second insulatinglayer 576 is directly on the first insulating layer 574 directly on thesidewalls of the lower fin portion 552A of the first fin 552 anddirectly on the sidewalls of the lower fin portion 562A of the secondfin 562.

A dielectric fill material 578 is directly laterally adjacent to thesecond insulating layer 576 directly on the first insulating layer 574directly on the sidewalls of the lower fin portion 552A of the first fin552 and directly on the sidewalls of the lower fin portion 562A of thesecond fin 562. In an embodiment, the dielectric fill material 578 hasan upper surface 578A, where a portion of the upper surface 578A of thedielectric fill material 578 is below at least one of the shoulderfeatures 554 of the first fin 552 and below at least one of the shoulderfeatures 564 of the second fin 562, as is depicted in FIG. 5B.

In an embodiment, the first insulating layer 574 is a non-dopedinsulating layer including silicon and oxygen, such as a silicon oxideor silicon dioxide insulating layer. In an embodiment, the firstinsulating layer 574 includes silicon and oxygen and has no other atomicspecies having an atomic concentration greater than 1E15 atoms per cubiccentimeter. In an embodiment, the first insulating layer 574 has athickness in the range of 0.5-2 nanometers.

In an embodiment, the second insulating layer 576 includes silicon andnitrogen, such as a stoichiometric Si₃N₄ silicon nitride insulatinglayer, a silicon-rich silicon nitride insulating layer, or asilicon-poor silicon nitride insulating layer. In an embodiment, thesecond insulating layer 576 has a thickness in the range of 2-5nanometers.

In an embodiment, the dielectric fill material 578 includes silicon andoxygen, such as a silicon oxide or silicon dioxide insulating layer. Inan embodiment, a gate electrode is ultimately formed over a top of andlaterally adjacent to sidewalls of the upper fin portion 552B of thefirst fin 552, and over a top of and laterally adjacent to sidewalls ofthe upper fin portion 562B of the second fin 562. The gate electrode isfurther over the dielectric fill material 578 between the first fin 552and the second fin 562.

FIGS. 6A-6D illustrate a cross-sectional view of various operations inthe fabrication of a three-layer trench isolation structure, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 6A, a method of fabricating an integrated circuitstructure includes forming a fin 602, such as a silicon fin. A firstinsulating layer 604 is formed directly on and conformal with the fin602, as is depicted in FIG. 6B. In an embodiment, the first insulatinglayer 604 includes silicon and oxygen and has no other atomic specieshaving an atomic concentration greater than 1E15 atoms per cubiccentimeter.

Referring to FIG. 6C, a second insulating layer 606 is formed directlyon and conformal with the first insulating layer 604. In an embodiment,the second insulating layer 606 includes silicon and nitrogen. Adielectric fill material 608 is formed directly on the second insulatinglayer 606, as is depicted in FIG. 6D.

In an embodiment, the method further involves recessing the dielectricfill material 608, the first insulating layer 604 and the secondinsulating layer 606 to provide the fin 602 having an exposed upper finportion 602A (e.g., such as upper fin portions 502B, 552B or 562B ofFIGS. 5A ad 5B). The resulting structure may be as described inassociation with FIG. 5A or 5B. In one embodiment, recessing thedielectric fill 608 material, the first insulating layer 604 and thesecond insulating layer 606 involves using a wet etch process. Inanother embodiment, recessing the dielectric fill 608 material, thefirst insulating layer 604 and the second insulating layer 606 involvesusing a plasma etch or dry etch process.

In an embodiment, the first insulating layer 604 is formed using achemical vapor deposition process. In an embodiment, the secondinsulating layer 606 is formed using a chemical vapor depositionprocess. In an embodiment, the dielectric fill material 608 is formedusing a spin-on process. In one such embodiment, the dielectric fillmaterial 608 is a spin-on material and is exposed to a steam treatment,e.g., either before or after a recess etch process, to provide a curedmaterial including silicon and oxygen. In an embodiment, a gateelectrode is ultimately formed over a top of and laterally adjacent tosidewalls of an upper fin portion of the fin 602.

In another aspect, gate sidewall spacer material may be retained overcertain trench isolation regions as a protection against erosion of thetrench isolation regions during subsequent processing operations. Forexample, FIGS. 7A-7E illustrate angled three-dimensional cross-sectionalviews of various operations in a method of fabricating an integratedcircuit structure, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 7A, a method of fabricating an integrated circuitstructure includes forming a fin 702, such as a silicon fin. The fin 702has a lower fin portion 702A and an upper fin portion 702B. Aninsulating structure 704 is formed directly adjacent sidewalls of thelower fin portion 702A of the fin 702. A gate structure 706 is formedover the upper fin portion 702B and over the insulating structure 704.In an embodiment, the gate structure is a placeholder or dummy gatestructure including a sacrificial gate dielectric layer 706A, asacrificial gate 706B, and a hardmask 706C. A dielectric material 708 isformed conformal with the upper fin portion 702B of the fin 702,conformal with the gate structure 706, and conformal with the insulatingstructure 704.

Referring to FIG. 7B, a hardmask material 710 is formed over thedielectric material 708. In an embodiment, the hardmask material 710 isa carbon-based hardmask material formed using a spin-on process.

Referring to FIG. 7C, the hardmask material 710 is recessed to form arecessed hardmask material 712 and to expose a portion of the dielectricmaterial 708 conformal with the upper fin portion 702B of the fin 702and conformal with the gate structure 706. The recessed hardmaskmaterial 712 covers a portion of the dielectric material 708 conformalwith the insulating structure 704. In an embodiment, the hardmaskmaterial 710 is recessed using a wet etching process. In anotherembodiment, the hardmask material 710 is recessed using an ash, a dryetch or a plasma etch process.

Referring to FIG. 7D, the dielectric material 708 is anisotropicallyetched to form a patterned dielectric material 714 along sidewalls ofthe gate structure 706 (as dielectric spacers 714A), along portions ofthe sidewalls of the upper fin portion 702B of the fin 702, and over theinsulating structure 704.

Referring to FIG. 7E, the recessed hardmask material 712 is removed fromthe structure of FIG. 7D. In an embodiment, the gate structure 706 is adummy gate structure, and subsequent processing includes replacing thegate structure 706 with a permanent gate dielectric and gate electrodestack. In an embodiment, further processing includes forming embeddedsource or drain structures on opposing sides of the gate structure 706,as is described in greater detail below.

Referring again to FIG. 7E, in an embodiment, an integrated circuitstructure 700 includes a first fin (left 702), such as a first siliconfin, the first fin having a lower fin portion 702A and an upper finportion 702B. The integrated circuit structure further includes a secondfin (right 702), such as a second silicon fin, the second fin having alower fin portion 702A and an upper fin portion 702B. An insulatingstructure 704 is directly adjacent sidewalls of the lower fin portion702A of the first fin and directly adjacent sidewalls of the lower finportion 702A of the second fin. A gate electrode 706 is over the upperfin portion 702B of the first fin (left 702), over the upper fin portion702B of the second fin (right 702), and over a first portion 704A of theinsulating structure 704. A first dielectric spacer 714A along asidewall of the upper fin portion 702B of the first fin (left 702), anda second dielectric spacer 702C is along a sidewall of the upper finportion 702B of the second fin (right 702). The second dielectric spacer714C is continuous with the first dielectric spacer 714B over a secondportion 704B of the insulating structure 704 between the first fin (left702 and the second fin (right 702).

In an embodiment, the first and second dielectric spacers 714B and 714Cinclude silicon and nitrogen, such as a stoichiometric Si₃N₄ siliconnitride material, a silicon-rich silicon nitride material, or asilicon-poor silicon nitride material.

In an embodiment, the integrated circuit structure 700 further includesembedded source or drain structures on opposing sides of the gateelectrode 706, the embedded source or drain structures having a bottomsurface below a top surface of the first and second dielectric spacers714B and 714C along the sidewalls of the upper fin portions 702B of thefirst and second fins 702, and the source or drain structures having atop surface above a top surface of the first and second dielectricspacers 714B and 714C along the sidewalls of the upper fin portions 702Bof the first and second fins 702, as is described below in associationwith FIG. 9B. In an embodiment, the insulating structure 704 includes afirst insulating layer, a second insulating layer directly on the firstinsulating layer, and a dielectric fill material directly laterally onthe second insulating layer, as is also described below in associationwith FIG. 9B.

FIGS. 8A-8F illustrate slightly projected cross-sectional views takenalong the a-a′ axis of FIG. 7E for various operations in a method offabricating an integrated circuit structure, in accordance with anembodiment of the present disclosure.

Referring to FIG. 8A, a method of fabricating an integrated circuitstructure includes forming a fin 702, such as a silicon fin. The fin 702has a lower fin portion (not seen in FIG. 8A) and an upper fin portion702B. An insulating structure 704 is formed directly adjacent sidewallsof the lower fin portion 702A of the fin 702. A pair of gate structures706 is formed over the upper fin portion 702B and over the insulatingstructure 704. It is to be appreciated that the perspective shown inFIGS. 8A-8F is slightly projected to show portions of the gatestructures 706 and insulating structure in front of (out of the page)the upper fin portion 702B, with the upper fin portion slightly into thepage. In an embodiment, the gate structures 706 are a placeholder ordummy gate structures including a sacrificial gate dielectric layer706A, a sacrificial gate 706B, and a hardmask 706C.

Referring to FIG. 8B, which corresponds to the process operationdescribed in association with FIG. 7A, a dielectric material 708 isformed conformal with the upper fin portion 702B of the fin 702,conformal with the gate structures 706, and conformal with exposedportions of the insulating structure 704.

Referring to FIG. 8C, which corresponds to the process operationdescribed in association with FIG. 7B, a hardmask material 710 is formedover the dielectric material 708. In an embodiment, the hardmaskmaterial 710 is a carbon-based hardmask material formed using a spin-onprocess.

Referring to FIG. 8D, which corresponds to the process operationdescribed in association with FIG. 7C, the hardmask material 710 isrecessed to form a recessed hardmask material 712 and to expose aportion of the dielectric material 708 conformal with the upper finportion 702B of the fin 702 and conformal with the gate structures 706.The recessed hardmask material 712 covers a portion of the dielectricmaterial 708 conformal with the insulating structure 704. In anembodiment, the hardmask material 710 is recessed using a wet etchingprocess. In another embodiment, the hardmask material 710 is recessedusing an ash, a dry etch or a plasma etch process.

Referring to FIG. 8E, which corresponds to the process operationdescribed in association with FIG. 7D, the dielectric material 708 isanisotropically etched to form a patterned dielectric material 714 alongsidewalls of the gate structure 706 (as portions 714A), along portionsof the sidewalls of the upper fin portion 702B of the fin 702, and overthe insulating structure 704.

Referring to FIG. 8F, which corresponds to the process operationdescribed in association with FIG. 7E, the recessed hardmask material712 is removed from the structure of FIG. 8E. In an embodiment, the gatestructures 706 are dummy gate structures, and subsequent processingincludes replacing the gate structures 706 with permanent gatedielectric and gate electrode stacks. In an embodiment, furtherprocessing includes forming embedded source or drain structures onopposing sides of the gate structure 706, as is described in greaterdetail below.

Referring again to FIG. 8F, in an embodiment, an integrated circuitstructure 700 includes a fin 702, such as a silicon fin, the fin 702having a lower fin portion (not viewed in FIG. 8F) and an upper finportion 702B. An insulating structure 704 is directly adjacent sidewallsof the lower fin portion of the fin 702. A first gate electrode (left706) is over the upper fin portion 702B and over a first portion 704A ofthe insulating structure 704. A second gate electrode (right 706) isover the upper fin portion 702B and over a second portion 704A′ of theinsulating structure 704. A first dielectric spacer (right 714A of left706) is along a sidewall of the first gate electrode (left 706), and asecond dielectric spacer (left 714A of right 706) is along a sidewall ofthe second gate electrode (right 706), the second dielectric spacercontinuous with the first dielectric spacer over a third portion 704A″of the insulating structure 704 between the first gate electrode (left706) and the second gate electrode (right 706).

FIG. 9A illustrates a slightly projected cross-sectional view takenalong the a-a′ axis of FIG. 7E for an integrated circuit structureincluding permanent gate stacks and epitaxial source or drain regions,in accordance with an embodiment of the present disclosure. FIG. 9Billustrates a cross-sectional view taken along the b-b′ axis of FIG. 7Efor an integrated circuit structure including epitaxial source or drainregions and a multi-layer trench isolation structure, in accordance withan embodiment of the present disclosure.

Referring to FIGS. 9A and 9B, in an embodiment, the integrated circuitstructure includes embedded source or drain structures 910 on opposingsides of the gate electrodes 706. The embedded source or drainstructures 910 have a bottom surface 910A below a top surface 990 of thefirst and second dielectric spacers 714B and 714C along the sidewalls ofthe upper fin portions 702B of the first and second fins 702. Theembedded source or drain structures 910 have a top surface 910B above atop surface of the first and second dielectric spacers 714B and 714Calong the sidewalls of the upper fin portions 702B of the first andsecond fins 702.

In an embodiment, gate stacks 706 are permanent gate stacks 920. In onesuch embodiment, the permanent gate stacks 920 include a gate dielectriclayer 922, a first gate layer 924, such as a workfunction gate layer,and a gate fill material 926, as is depicted in FIG. 9A. In oneembodiment, where the permanent gate structures 920 are over theinsulating structure 704, the permanent gate structures 920 are formedon residual polycrystalline silicon portions 930, which may be remnantsof a replacement gate process involving sacrificial polycrystallinesilicon gate electrodes.

In an embodiment, the insulating structure 704 includes a firstinsulating layer 902, a second insulating layer 904 directly on thefirst insulating layer 902, and a dielectric fill material 906 directlylaterally on the second insulating layer 904. In one embodiment, thefirst insulating layer 902 is a non-doped insulating layer includingsilicon and oxygen. In one embodiment, the second insulating layer 904includes silicon and nitrogen. In one embodiment, the dielectric fillmaterial 906 includes silicon and oxygen.

In another aspect, epitaxial embedded source or drain regions areimplemented as source or drain structures for semiconductor fins. As anexample, FIG. 10 illustrates a cross-sectional view of an integratedcircuit structure taken at a source or drain location, in accordancewith an embodiment of the present disclosure.

Referring to FIG. 10, an integrated circuit structure 1000 includes aP-type device, such as a P-type Metal Oxide Semiconductor (PMOS) device.The integrated circuit structure 1000 also includes an N-type device,such as an N-type Metal Oxide Semiconductor (PMOS) device.

The PMOS device of FIG. 10 includes a first plurality of semiconductorfins 1002, such as silicon fins formed from a bulk silicon substrate1001. At the source or drain location, upper portions of the fins 1002have been removed, and a same or different semiconductor material isgrown to form source or drain structures 1004. It is to be appreciatedthat the source or drain structures 1004 will look the same at across-sectional view taken on either side of a gate electrode, e.g.,they will look essentially the same at a source side as at a drain side.In an embodiment, as depicted, the source or drain structures 1004 havea portion below and a portion above an upper surface of an insulatingstructure 1006. In an embodiment, as depicted, the source or drainstructures 1004 are strongly faceted. In an embodiment, a conductivecontact 1008 is formed over the source or drain structures 1004. In onesuch embodiment, however, the strong faceting, and the relatively widegrowth of the source or drain structures 1004 inhibits good coverage bythe conductive contact 1008 at least to some extent.

The NMOS device of FIG. 10 includes a second plurality of semiconductorfins 1052, such as silicon fins formed from the bulk silicon substrate1001. At the source or drain location, upper portions of the fins 1052have been removed, and a same or different semiconductor material isgrown to form source or drain structures 1054. It is to be appreciatedthat the source or drain structures 1054 will look the same at across-sectional view taken on either side of a gate electrode, e.g.,they will look essentially the same at a source side as at a drain side.In an embodiment, as depicted, the source or drain structures 1054 havea portion below and a portion above an upper surface of the insulatingstructure 1006. In an embodiment, as depicted, the source or drainstructures 1054 are weakly faceted relative to the source or drainstructures 1004. In an embodiment, a conductive contact 1058 is formedover the source or drain structures 1054. In one such embodiment,relatively weak faceting, and the resulting relatively narrower growthof the source or drain structures 1054 (as compared with the source ordrain structures 1004) enhances good coverage by the conductive contact1058.

The shape of the source or drain structures of a PMOS device may bevaried to improve contact area with an overlying contact. For example,FIG. 11 illustrates a cross-sectional view of another integrated circuitstructure taken at a source or drain location, in accordance with anembodiment of the present disclosure.

Referring to FIG. 11, an integrated circuit structure 1100 includes aP-type semiconductor (e.g., PMOS) device. The PMOS device includes afirst fin 1102, such as a silicon fin. A first epitaxial source or drainstructure 1104 is embedded in the first fin 1102. In one embodiment,although not depicted, the first epitaxial source or drain structure1104 is at a first side of a first gate electrode (which may be formedover an upper fin portion such as a channel portion of the fin 1102),and a second epitaxial source or drain structure is embedded in thefirst fin 1102 at a second side of such a first gate electrode oppositethe first side. In an embodiment, the first 1104 and second epitaxialsource or drain structures include silicon and germanium and have aprofile 1105. In one embodiment, the profile is a match-stick profile,as depicted in FIG. 11. A first conductive electrode 1108 is over thefirst epitaxial source or drain structure 1104.

Referring again to FIG. 11, in an embodiment, the integrated circuitstructure 1100 also includes an N-type semiconductor (e.g., NMOS)device. The NMOS device includes a second fin 1152, such as a siliconfin. A third epitaxial source or drain structure 1154 is embedded in thesecond fin 1152. In one embodiment, although not depicted, the thirdepitaxial source or drain structure 1154 is at a first side of a secondgate electrode (which may be formed over an upper fin portion such as achannel portion of the fin 1152), and a fourth epitaxial source or drainstructure is embedded in the second fin 1152 at a second side of such asecond gate electrode opposite the first side. In an embodiment, thethird 1154 and fourth epitaxial source or drain structures includesilicon and have substantially the same profile as the profile 1105 ofthe first and second epitaxial source or drain structures 1004. A secondconductive electrode 1158 is over the third epitaxial source or drainstructure 1154.

In an embodiment, the first epitaxial source or drain structure 1104 isweakly faceted. In an embodiment, the first epitaxial source or drainstructure 1104 has a height of approximately 50 nanometers and has awidth in the range of 30-35 nanometers. In one such embodiment, thethird epitaxial source or drain structure 1154 has a height ofapproximately 50 nanometers and has a width in the range of 30-35nanometers.

In an embodiment, the first epitaxial source or drain structure 1104 isgraded with an approximately 20% germanium concentration at a bottom1104A of the first epitaxial source or drain structure 1104 to anapproximately 45% germanium concentration at a top 1104B of the firstepitaxial source or drain structure 1104. In an embodiment, the firstepitaxial source or drain structure 1104 is doped with boron atoms. Inone such embodiment, the third epitaxial source or drain structure 1154is doped with phosphorous atoms or arsenic atoms.

FIGS. 12A-12D illustrate cross-sectional views taken at a source ordrain location and representing various operations in the fabrication ofan integrated circuit structure, in accordance with an embodiment of thepresent disclosure.

Referring to FIG. 12A, a method of fabricating an integrated circuitstructure includes forming a fin, such as a silicon fin formed from asilicon substrate 1201. The fin 1202 has a lower fin portion 1202A andan upper fin portion 1202B. In an embodiment, although not depicted, agate electrode is formed over a portion of the upper fin portion 1202Bof the fin 1202 at a location into the page. Such a gate electrode has afirst side opposite a second side and defines source or drain locationson the first and second sides. For example, for the purposes ofillustration, the cross-sectional locations for the views of FIGS.12A-12D are taken at one of the source or drain locations at one of thesides of a gate electrode.

Referring to FIG. 12B, a source of drain location of the fin 1202 isrecessed to form recessed fin portion 1206. The recessed source or drainlocation of the fin 1202 may be at a side of a gate electrode and at thesecond side of the gate electrode. Referring to both FIGS. 12A and 12B,in an embodiment, dielectric spacers 1204 are formed along sidewalls ofa portion of the fin 1202, e.g., at a side of a gate structure. In onesuch embodiment, recessing the fin 1202 involves recessing the fin 1202below a top surface 1204A of the dielectric spacers 1204.

Referring to FIG. 12C, an epitaxial source or drain structure 1208 isformed on the recessed fin 1206, e.g., and thus may be formed at a sideof a gate electrode. In one such embodiment, a second epitaxial sourceor drain structure is formed on a second portion of the recessed fin1206 at a second side of such a gate electrode. In an embodiment, theepitaxial source or drain structure 1208 includes silicon and germanium,and has a match-stick profile, as is depicted in FIG. 12C. In anembodiment, dielectric spacers 1204 are included and are along a lowerportion 1208A of sidewalls of the epitaxial source or drain structure1208, as depicted.

Referring to FIG. 12D, a conductive electrode 1210 is formed on theepitaxial source or drain structure 1208. In an embodiment, theconductive electrode 1210 includes a conductive barrier layer 1210A anda conductive fill material 1201B. In one embodiment, the conductiveelectrode 1210 follows the profile of the epitaxial source or drainstructure 1208, as is depicted. In other embodiments, upper portions ofthe epitaxial source or drain structure 1208 are eroded duringfabrication of the conductive electrode 1210.

In another aspect, fin-trim isolation (FTI) and single gate spacing forisolated fins is described. Non-planar transistors which utilize a finof semiconductor material protruding from a substrate surface employ agate electrode that wraps around two, three, or even all sides of thefin (i.e., dual-gate, tri-gate, nanowire transistors). Source and drainregions are typically then formed in the fin, or as re-grown portions ofthe fin, on either side of the gate electrode. To isolate a source ordrain region of a first non-planar transistor from a source or drainregion of an adjacent second non-planar transistor, a gap or space maybe formed between two adjacent fins. Such an isolation gap generallyrequires a masked etch of some sort. Once isolated, a gate stack is thenpatterned over the individual fins, again typically with a masked etchof some sort (e.g., a line etch or an opening etch depending on thespecific implementation).

One potential issue with the fin isolation techniques described above isthat the gates are not self-aligned with the ends of the fins, andalignment of the gate stack pattern with the semiconductor fin patternrelies on overlay of these two patterns. As such, lithographic overlaytolerances are added into the dimensioning of the semiconductor fin andthe isolation gap with fins needing to be of greater length andisolation gaps larger than they would be otherwise for a given level oftransistor functionality. Device architectures and fabricationtechniques that reduce such over-dimensioning therefore offer highlyadvantageous improvements in transistor density.

Another potential issue with the fin isolation techniques described inthe above is that stress in the semiconductor fin desirable forimproving carrier mobility may be lost from the channel region of thetransistor where too many fin surfaces are left free during fabrication,allowing fin strain to relax. Device architectures and fabricationtechniques that maintain higher levels of desirable fin stress thereforeoffer advantageous improvements in non-planar transistor performance.

In accordance with an embodiment of the present disclosure, through-gatefin isolation architectures and techniques are described herein. In theexemplary embodiments illustrated, non-planar transistors in amicroelectronic device, such as an integrated circuit (IC) are isolatedfrom one another in a manner that is self-aligned to gate electrodes ofthe transistors. Although embodiments of the present disclosure areapplicable to virtually any IC employing non-planar transistors,exemplary ICs include, but are not limited to, microprocessor coresincluding logic and memory (SRAM) portions, RFICs (e.g., wireless ICsincluding digital baseband and analog front end modules), and power ICs.

In embodiments, two ends of adjacent semiconductor fins are electricallyisolated from each other with an isolation region that is positionedrelative to gate electrodes with the use of only one patterning masklevel. In an embodiment, a single mask is employed to form a pluralityof sacrificial placeholder stripes of a fixed pitch, a first subset ofthe placeholder stripes define a location or dimension of isolationregions while a second subset of the placeholder stripes defines alocation or dimension of a gate electrode. In certain embodiments, thefirst subset of placeholder stripes is removed and isolation cuts madeinto the semiconductor fins in the openings resulting from the firstsubset removal while the second subset of the placeholder stripes isultimately replaced with non-sacrificial gate electrode stacks. Since asubset of placeholders utilized for gate electrode replacement areemployed to form the isolation regions, the method and resultingarchitecture is referred to herein as “through-gate” isolation. One ormore through-gate isolation embodiments described herein may, forexample, enable higher transistor densities and higher levels ofadvantageous transistor channel stress.

With isolation defined after placement or definition of the gateelectrode, a greater transistor density can be achieved because finisolation dimensioning and placement can be made perfectly on-pitch withthe gate electrodes so that both gate electrodes and isolation regionsare integer multiples of a minimum feature pitch of a single maskinglevel. In further embodiments where the semiconductor fin has a latticemismatch with a substrate on which the fin is disposed, greater degreesof strain are maintained by defining the isolation after placement ordefinition of the gate electrode. For such embodiments, other featuresof the transistor (such as the gate electrode and added source or drainmaterials) that are formed before ends of the fin are defined help tomechanically maintain fin strain after an isolation cut is made into thefin.

To provide further context, transistor scaling can benefit from a denserpacking of cells within the chip. Currently, most cells are separatedfrom their neighbors by two or more dummy gates, which have buried fins.The cells are isolated by etching the fins beneath these two or moredummy gates, which connect one cell to the other. Scaling can benefitsignificantly if the number of dummy gates that separate neighboringcells can be reduced from two or more down to one. As explained above,one solution requires two or more dummy gates. The fins under the two ormore dummy gates are etched during fin patterning. A potential issuewith such an approach is that dummy gates consume space on the chipwhich can be used for cells. In an embodiment, approaches describedherein enable the use of only a single dummy gate to separateneighboring cells.

In an embodiment, a fin trim isolation approach is implemented as aself-aligned patterning scheme. Here, the fins beneath a single gate areetched out. Thus, neighboring cells can be separated by a single dummygate. Advantages to such an approach may include saving space on thechip and allowing for more computational power for a given area. Theapproach may also allow for fin trim to be performed at a sub-fin pitchdistance.

FIGS. 13A and 13B illustrate plan views representing various operationsin a method of patterning of fins with multi-gate spacing for forming alocal isolation structure, in accordance with an embodiment of thepresent disclosure.

Referring to FIG. 13A, a plurality of fins 1302 is shown having a lengthalong a first direction 1304. A grid 1306, having spacings 1307 therebetween, defining locations for ultimately forming a plurality of gatelines is shown along a second direction 1308 orthogonal to the firstdirection 1304.

Referring to FIG. 13B, a portion of the plurality of fins 1302 is cut(e.g., removed by an etch process) to leave fins 1310 having a cut 1312therein. An isolation structure ultimately formed in the cut 1312therefore has a dimension of more than a single gate line, e.g., adimension of three gate lines 1306. Accordingly, gate structuresultimately formed along the locations of the gate lines 1306 will beformed at least partially over an isolation structure formed in cut1312. Thus, cut 1312 is a relatively wide fin cut.

FIGS. 14A-14D illustrate plan views representing various operations in amethod of patterning of fins with single gate spacing for forming alocal isolation structure, in accordance with another embodiment of thepresent disclosure.

Referring to FIG. 14A, a method of fabricating an integrated circuitstructure includes forming a plurality of fins 1402, individual ones ofthe plurality of fins 1402 having a longest dimension along a firstdirection 1404. A plurality of gate structures 1406 is over theplurality of fins 1402, individual ones of the gate structures 1406having a longest dimension along a second direction 1408 orthogonal tothe first direction 1404. In an embodiment, the gate structures 1406 aresacrificial or dummy gate lines, e.g., fabricated from polycrystallinesilicon. In one embodiment, the plurality of fins 1402 are silicon finsand are continuous with a portion of an underlying silicon substrate.

Referring to FIG. 14B, a dielectric material structure 1410 is formedbetween adjacent ones of the plurality of gate structures 1406.

Referring to FIG. 14C, a portion 1412 of one of the plurality of gatestructures 1406 is removed to expose a portion 1414 of each of theplurality of fins 1402. In an embodiment, removing the portion 1412 ofthe one of the plurality of gate structures 1406 involves using alithographic window 1416 wider than a width 1418 of the portion 1412 ofthe one of the plurality of gate structures 1406.

Referring to FIG. 14D, the exposed portion 1414 of each of the pluralityof fins 1402 is removed to form a cut region 1420. In an embodiment, theexposed portion 1414 of each of the plurality of fins 1402 is removedusing a dry or plasma etch process. In an embodiment, removing theexposed portion 1414 of each of the plurality of fins 1402 involvesetching to a depth less than a height of the plurality of fins 1402. Inone such embodiment, the depth is greater than a depth of source ordrain regions in the plurality of fins 1402. In an embodiment, the depthis deeper than a depth of an active portion of the plurality of fins1402 to provide isolation margin. In an embodiment, the exposed portion1414 of each of the plurality of fins 1402 is removed without etching orwithout substantially etching source or drain regions (such as epitaxialsource or drain regions) of the plurality of fins 1402. In one suchembodiment, the exposed portion 1414 of each of the plurality of fins1402 is removed without laterally etching or without substantiallylaterally etching source or drain regions (such as epitaxial source ordrain regions) of the plurality of fins 1402.

In an embodiment, the cut region 1420 is ultimately filled with aninsulating layer, e.g., in locations of the removed portion 1414 of eachof the plurality of fins 1402. Exemplary insulating layers or “poly cut”or “plug” structure are described below. In other embodiments, however,the cut region 1420 is only partially filled with an insulating layer inwhich a conductive structure is then formed. The conductive structuremay be used as a local interconnect. In an embodiment, prior to fillingthe cut region 1420 with an insulating layer or with an insulating layerhousing a local interconnect structure, dopants may be implanted ordelivered by a solid source dopant layer into the locally cut portion ofthe fin or fins through the cut region 1420.

FIG. 15 illustrates a cross-sectional view of an integrated circuitstructure having a fin with multi-gate spacing for local isolation, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 15, a silicon fin 1502 has a first fin portion 1504laterally adjacent a second fin portion 1506. The first fin portion 1504is separated from the second fin portion 1506 by a relatively wide cut1508, such as described in association with FIGS. 13A and 13B, therelatively wide cut 1508 having a width X. A dielectric fill material1510 is formed in the relatively wide cut 1508 and electrically isolatesthe first fin portion 1504 from the second fin portion 1506. A pluralityof gate lines 1512 is over the silicon fin 1502, where each of the gatelines may include a gate dielectric and gate electrode stack 1514, adielectric cap layer 1516, and sidewall spacers 1518. Two gate lines(left two gate lines 1512) occupy the relatively wide cut 1508 and, assuch, the first fin portion 1504 is separated from the second finportion 1506 by effectively two dummy or inactive gates.

By contrast, fin portions may be separated by a single gate distance. Asan example, FIG. 16A illustrates a cross-sectional view of an integratedcircuit structure having a fin with single gate spacing for localisolation, in accordance with another embodiment of the presentdisclosure.

Referring to FIG. 16A, a silicon fin 1602 has a first fin portion 1604laterally adjacent a second fin portion 1606. The first fin portion 1604is separated from the second fin portion 1606 by a relatively narrow cut1608, such as described in association with FIGS. 14A-14D, therelatively narrow cut 1608 having a width Y, where Y is less than X ofFIG. 15. A dielectric fill material 1610 is formed in the relativelynarrow cut 1608 and electrically isolates the first fin portion 1604from the second fin portion 1606. A plurality of gate lines 1612 is overthe silicon fin 1602, where each of the gate lines may include a gatedielectric and gate electrode stack 1614, a dielectric cap layer 1616,and sidewall spacers 1618. The dielectric fill material 1610 occupiesthe location where a single gate line was previously and, as such, thefirst fin portion 1604 is separated from the second fin portion 1606 bysingle “plugged” gate line. In one embodiment, residual spacer material1620 remains on the sidewalls of the location of the removed gate lineportion, as depicted. It is to be appreciated that other regions of thefin 1602 may be isolated from one another by two or even more inactivegate lines (region 1622 having three inactive gate lines) fabricated byan earlier, broader fin cut process, as described below.

Referring again to FIG. 16A, an integrated circuit structure 1600 a fin1602, such as a silicon fin. The fin 1602 has a longest dimension alonga first direction 1650. An isolation structure 1610 separates a firstupper portion 1604 of the fin 1602 from a second upper portion 1606 ofthe fin 1602 along the first direction 1650. The isolation structure1610 has a center 1611 along the first direction 1650.

A first gate structure 1612A is over the first upper portion 1604 of thefin 1602, the first gate structure 1612A has a longest dimension along asecond direction 1652 (e.g., into the page) orthogonal to the firstdirection 1650. A center 1613A of the first gate structure 1612A isspaced apart from the center 1611 of the isolation structure 1610 by apitch along the first direction 1650. A second gate structure 1612B isover the first upper portion 1604 of the fin, the second gate structure1612B having a longest dimension along the second direction 1652. Acenter 1613B of the second gate structure 1612B is spaced apart from thecenter 1613A of the first gate structure 1612A by the pitch along thefirst direction 1650. A third gate structure 1612C is over the secondupper portion 1606 of the fin 1602, the third gate structure 1612Chaving a longest dimension along the second direction 1652. A center1613C of the third gate structure 1612C is spaced apart from the center1611 of the isolation structure 1610 by the pitch along the firstdirection 1650. In an embodiment, the isolation structure 1610 has a topsubstantially co-planar with a top of the first gate structure 1612A,with a top of the second gate structure 1612B, and with a top of thethird gate structure 1612C, as is depicted.

In an embodiment, each of the first gate structure 1612A, the secondgate structure 1612B and the third gate structure 1612C includes a gateelectrode 1660 on and between sidewalls of a high-k gate dielectriclayer 1662, as is illustrated for exemplary third gate structure 1612C.In one such embodiment, each of the first gate structure 1612A, thesecond gate structure 1612B and the third gate structure 1612C furtherincludes an insulating cap 1616 on the gate electrode 1660 and on andthe sidewalls of the high-k gate dielectric layer 1662.

In an embodiment, the integrated circuit structure 1600 further includesa first epitaxial semiconductor region 1664A on the first upper portion1604 of the fin 1602 between the first gate structure 1612A and theisolation structure 1610. A second epitaxial semiconductor region 1664Bis on the first upper portion 1604 of the fin 1602 between the firstgate structure 1612A and the second gate structure 1612B. A thirdepitaxial semiconductor region 1664C is on the second upper portion 1606of the fin 1602 between the third gate structure 1612C and the isolationstructure 1610. In one embodiment, the first 1664A, second 1664B andthird 1664C epitaxial semiconductor regions include silicon andgermanium. In another embodiment, the first 1664A, second 1664B andthird 1664C epitaxial semiconductor regions include silicon.

In an embodiment, the isolation structure 1610 induces a stress on thefirst upper portion 1604 of the fin 1602 and on the second upper portion1606 of the fin 1602. In one embodiment, the stress is a compressivestress. In another embodiment, the stress is a tensile stress. In otherembodiments, the isolation structure 1610 is a partially fillinginsulating layer in which a conductive structure is then formed. Theconductive structure may be used as a local interconnect. In anembodiment, prior to forming the isolation structure 1610 with aninsulating layer or with an insulating layer housing a localinterconnect structure, dopants are implanted or delivered by a solidsource dopant layer into a locally cut portion of the fin or fins.

In another aspect, it is to be appreciated that isolation structuressuch as isolation structure 1610 described above may be formed in placeof active gate electrode at local locations of a fin cut or at broaderlocations of a fin cut. Additionally, the depth of such local or broaderlocations of fin cut may be formed to varying depths within the finrelative to one another. In a first example, FIG. 16B illustrates across-sectional view showing locations where a fin isolation structuremay be formed in place of a gate electrode, in accordance with anembodiment of the present disclosure.

Referring to FIG. 16B, a fin 1680, such as a silicon fin, is formedabove and may be continuous with a substrate 1682. The fin 1680 has finends or broad fin cuts 1684, e.g., which may be formed at the time offin patterning such as in a fin trim last approach described above. Thefin 1680 also has a local cut 1686, where a portion of the fin 1680 isremoved, e.g., using a fin trim isolation approach where dummy gates arereplaced with dielectric plugs, as described above. Active gateelectrodes 1688 are formed over the fin and, for the sake ofillustration purposes, are shown slightly in front of the fin 1680, withthe fin 1680 in the background, where the dashed lines represent areascovered from the front view. Dielectric plugs 1690 may be formed at thefin ends or broad fin cuts 1684 in place of using active gates at suchlocations. In addition, or in the alternative, a dielectric plug 1692may be formed at the local cut 1686 in place of using an active gate atsuch a location. It is to be appreciated that epitaxial source or drainregions 1694 are also shown at locations of the fins 1680 between theactive gate electrodes 1688 and the plugs 1690 or 1692. Additionally, inan embodiment, the surface roughness of the ends of the fin at the localcut 1686 are rougher than the ends of the fin at a location of a broadercut, as is depicted in FIG. 16B.

FIGS. 17A-17C illustrate various depth possibilities for a fin cutfabricated using fin trim isolation approach, in accordance with anembodiment of the preset disclosure.

Referring to FIG. 17A, a semiconductor fin 1700, such as a silicon fin,is formed above and may be continuous with an underlying substrate 1702.The fin 1700 has a lower fin portion 1700A and an upper fin portion1700B, as defined by the height of an insulating structure 1704 relativeto the fin 1700. A local fin isolation cut 1706A separates the fin 1700into a first fin portion 1710 from a second fin portion 1712. In theexample of FIG. 17A, as shown along the a-a′ axis, the depth of thelocal fin isolation cut 1706A is the entire depth of the fin 1700 to thesubstrate 1702.

Referring to FIG. 17B, in a second example, as shown along the a-a′axis, the depth of a local fin isolation cut 1706B is deeper than theentire depth of the fin 1700 to the substrate 1702. That is, the cut1706B extends into the underlying substrate 1702.

Referring to FIG. 17C, in a third example, as shown along the a-a′ axis,the depth of a local fin isolation cut 1706C is less than the entiredepth of the fin 1700, but is deeper than an upper surface of theisolation structure 1704. Referring again to FIG. 17C, in a fourthexample, as shown along the a-a′ axis, the depth of a local finisolation cut 1706D is less than the entire depth of the fin 1700, andis at a level approximately co-planar with an upper surface of theisolation structure 1704.

FIG. 18 illustrates a plan view and corresponding cross-sectional viewtaken along the a-a′ axis showing possible options for the depth oflocal versus broader locations of fin cuts within a fin, in accordancewith an embodiment of the present disclosure.

Referring to FIG. 18, first and second semiconductor fins 1800 and 1802,such as silicon fins, have upper fin portions 1800B and 1802B extendingabove an insulating structure 1804. Both of the fins 1800 and 1802 havefin ends or broad fin cuts 1806, e.g., which may be formed at the timeof fin patterning such as in a fin trim last approach described above.Both of the fins 1800 and 1802 also have a local cut 1808, where aportion of the fin 1800 or 1802 is removed, e.g., using a fin trimisolation approach where dummy gates are replaced with dielectric plugs,as described above. In an embodiment, the surface roughness of the endsof the fins 1800 and 1802 at the local cut 1808 are rougher than theends of the fins at a location of 1806, as is depicted in FIG. 18.

Referring to the cross-sectional view of FIG. 18, lower fin portions1800A and 1802A can be viewed below the height of the insulatingstructure 1804. Also, seen in the cross-sectional view is a remnantportion 1810 of a fin that was removed at a fin trim last process priorto formation of the insulating structure 1804, as described above.Although shown as protruding above a substrate, remnant portion 1810could also be at the level of the substrate or into the substrate, as isdepicted by the additional exemplary broad cut depths 1820. It is to beappreciated that the broad cuts 1806 for fins 1800 and 1802 may also beat the levels described for cut depth 1820, examples of which aredepicted. The local cut 1808 can have exemplary depths corresponding tothe depths described for FIGS. 17A-17C, as is depicted.

Referring collectively to FIGS. 16A, 16B, 17A-17C and 18, in accordancewith an embodiment of the present disclosure, an integrated circuitstructure includes a fin including silicon, the fin having a top andsidewalls, where the top has a longest dimension along a firstdirection. A first isolation structure separates a first end of a firstportion of the fin from a first end of a second portion of the fin alongthe first direction. The first isolation structure has a width along thefirst direction. The first end of the first portion of the fin has asurface roughness. A gate structure includes a gate electrode over thetop of and laterally adjacent to the sidewalls of a region of the firstportion of the fin. The gate structure has the width along the firstdirection, and a center of the gate structure is spaced apart from acenter of the first isolation structure by a pitch along the firstdirection. A second isolation structure is over a second end of a firstportion of the fin, the second end opposite the first end. The secondisolation structure has the width along the first direction, and thesecond end of the first portion of the fin has a surface roughness lessthan the surface roughness of the first end of the first portion of thefin. A center of the second isolation structure is spaced apart from thecenter of the gate structure by the pitch along the first direction.

In one embodiment, the first end of the first portion of the fin has ascalloped topography, as is depicted in FIG. 16B. In one embodiment, afirst epitaxial semiconductor region is on the first portion of the finbetween the gate structure and the first isolation structure. A secondepitaxial semiconductor region is on the first portion of the finbetween the gate structure and the second isolation structure. In oneembodiment, the first and second epitaxial semiconductor regions have awidth along a second direction orthogonal to the first direction, thewidth along the second direction wider than a width of the first portionof the fin along the second direction beneath the gate structure, e.g.,as epitaxial features described in association with FIGS. 11 and 12Dwhich have a width wider than the fin portions on which they are grownin the perspective shown in FIGS. 11 and 12D. In one embodiment, thegate structure further includes a high-k dielectric layer between thegate electrode and the first portion of the fin and along sidewalls ofthe gate electrode.

Referring collectively to FIGS. 16A, 16B, 17A-17C and 18, in accordancewith another embodiment of the present disclosure, an integrated circuitstructure includes a fin including silicon, the fin having a top andsidewalls, wherein the top has a longest dimension along a direction. Afirst isolation structure separates a first end of a first portion ofthe fin from a first end of a second portion of the fin along thedirection. The first end of the first portion of the fin has a depth. Agate structure includes a gate electrode over the top of and laterallyadjacent to the sidewalls of a region of the first portion of the fin. Asecond isolation structure is over a second end of a first portion ofthe fin, the second end opposite the first end. The second end of thefirst portion of the fin has a depth different than the depth of thefirst end of the first portion of the fin.

In one embodiment, the depth of the second end of the first portion ofthe fin is less than the depth of the first end of the first portion ofthe fin. In one embodiment, the depth of the second end of the firstportion of the fin is greater than the depth of the first end of thefirst portion of the fin. In one embodiment, the first isolationstructure has a width along the direction, and the gate structure hasthe width along the direction. The second isolation structure has thewidth along the direction. In one embodiment, a center of the gatestructure is spaced apart from a center of the first isolation structureby a pitch along the direction, and a center of the second isolationstructure is spaced apart from the center of the gate structure by thepitch along the direction.

Referring collectively to FIGS. 16A, 16B, 17A-17C and 18, in accordancewith another embodiment of the present disclosure, an integrated circuitstructure includes a first fin including silicon, the first fin having atop and sidewalls, where the top has a longest dimension along adirection, and a discontinuity separates a first end of a first portionof the first fin from a first end of a second portion of the fin alongthe direction. The first portion of the first fin has a second endopposite the first end, and the first end of the first portion of thefin has a depth. The integrated circuit structures also includes asecond fin including silicon, the second fin having a top and sidewalls,where the top has a longest dimension along the direction. Theintegrated circuit structure also includes a remnant or residual finportion between the first fin and the second fin. The residual finportion has a top and sidewalls, where the top has a longest dimensionalong the direction, and the top is non-co-planar with the depth of thefirst end of the first portion of the fin.

In one embodiment, the depth of the first end of the first portion ofthe fin is below the top of the remnant or residual fin portion. In oneembodiment, the second end of the first portion of the fin has a depthco-planar with the depth of the first end of the first portion of thefin. In one embodiment, the second end of the first portion of the finhas a depth below the depth of the first end of the first portion of thefin. In one embodiment, the second end of the first portion of the finhas a depth above the depth of the first end of the first portion of thefin. In one embodiment, the depth of the first end of the first portionof the fin is above the top of the remnant or residual fin portion. Inone embodiment, the second end of the first portion of the fin has adepth co-planar with the depth of the first end of the first portion ofthe fin. In one embodiment, the second end of the first portion of thefin has a depth below the depth of the first end of the first portion ofthe fin. In one embodiment, the second end of the first portion of thefin has a depth above the depth of the first end of the first portion ofthe fin. In one embodiment, the second end of the first portion of thefin has a depth co-planar with the top of the residual fin portion. Inone embodiment, the second end of the first portion of the fin has adepth below the top of the residual fin portion. In one embodiment, thesecond end of the first portion of the fin has a depth above the top ofthe residual fin portion.

In another aspect, dielectric plugs formed in locations of local orbroad fin cuts can be tailored to provide a particular stress to the finor fin portion. The dielectric plugs may be referred to as fin endstressors in such implementations.

One or more embodiments are directed to the fabrication of fin-basedsemiconductor devices. Performance improvement for such devices may bemade via channel stress induced from a poly plug fill process.Embodiments may include the exploitation of material properties in apoly plug fill process to induce mechanical stress in a metal oxidesemiconductor field effect transistor (MOSFET) channel. As a result, aninduced stress can boost the mobility and drive current of thetransistor. In addition, a method of plug fill described herein mayallow for the elimination of any seam or void formation duringdeposition.

To provide context, manipulating unique material properties of a plugfill that abuts fins can induce stress within the channel. In accordancewith one or more embodiments, by tuning the composition, deposition, andpost-treatment conditions of the plug fill material, stress in thechannel is modulated to benefit both NMOS and PMOS transistors. Inaddition, such plugs can reside deeper in the fin substrate compared toother common stressor techniques, such as epitaxial source or drains.The nature of the plug fill to achieve such effect also eliminates seamsor voids during deposition and mitigates certain defect modes during theprocess.

To provide further context, presently there is no intentional stressengineering for gate (poly) plugs. The stress enhancement fromtraditional stressors such as epitaxial source or drains, dummy polygate removal, stress liners, etc. unfortunately tends to diminish asdevice pitches shrink. Addressing one or more of the above issues, inaccordance with one or more embodiments of the present disclosure, anadditional source of stress is incorporated into the transistorstructure. Another possible benefit with such a process may be theelimination of seams or voids within the plug that may be common withother chemical vapor deposition methods.

FIGS. 19A and 19B illustrate cross-sectional views of various operationsin a method of selecting fin end stressor locations at ends of a finthat has a broad cut, e.g., as part of a fin trim last process asdescribed above, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 19A, a fin 1900, such as a silicon fin, is formedabove and may be continuous with a substrate 1902. The fin 1900 has finends or broad fin cuts 1904, e.g., which may be formed at the time offin patterning such as in a fin trim last approach described above. Anactive gate electrode location 1906 and dummy gate electrode locations1908 are formed over the fin 1900 and, for the sake of illustrationpurposes, are shown slightly in front of the fin 1900, with the fin 1900in the background, where the dashed lines represent areas covered fromthe front view. It is to be appreciated that epitaxial source or drainregions 1910 are also shown at locations of the fin 1900 between thegate locations 1906 and 1908. Additionally, an inter-layer dielectricmaterial 1912 is included at locations of the fin 1900 between the gatelocations 1906 and 1908.

Referring to FIG. 19B, the gate placeholder structures or dummy gateslocations 1908 are removed, exposing the fin ends or broad fin cuts1904. The removal creates openings 1920 where dielectric plugs, e.g.,fin end stressor dielectric plugs, may ultimately be formed.

FIGS. 20A and 20B illustrate cross-sectional views of various operationsin a method of selecting fin end stressor locations at ends of a finthat has a local cut, e.g., as part of a fin trim isolation process asdescribed above, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 20A, a fin 2000, such as a silicon fin, is formedabove and may be continuous with a substrate 2002. The fin 2000 has alocal cut 2004, where a portion of the fin 2000 is removed, e.g., usinga fin trim isolation approach where a dummy gate is removed and the finis etched in a local location, as described above. Active gate electrodelocations 2006 and a dummy gate electrode location 2008 are formed overthe fin 2000 and, for the sake of illustration purposes, are shownslightly in front of the fin 2000, with the fin 2000 in the background,where the dashed lines represent areas covered from the front view. Itis to be appreciated that epitaxial source or drain regions 2010 arealso shown at locations of the fin 2000 between the gate locations 2006and 2008. Additionally, an inter-layer dielectric material 2012 isincluded at locations of the fin 2000 between the gate locations 2006and 2008.

Referring to FIG. 20B, the gate placeholder structure or dummy gateelectrode location 2008 is removed, exposing the fin ends with local cut2004. The removal creates opening 2020 where a dielectric plug, e.g., afin end stressor dielectric plug, may ultimately be formed.

FIGS. 21A-21M illustrate cross-sectional views of various operation in amethod of fabricating an integrated circuit structure havingdifferentiated fin end dielectric plugs, in accordance with anembodiment of the present disclosure.

Referring to FIG. 21A, a starting structure 2100 includes an NMOS regionand a PMOS region. The NMOS region of the starting structure 2100includes a first fin 2102, such as a first silicon fin, which is formedabove and may be continuous with a substrate 2104. The first fin 2102has fin ends 2106 which may be formed from local or broad fin cuts. Afirst active gate electrode location 2108 and first dummy gate electrodelocations 2110 are formed over the first fin 2102 and, for the sake ofillustration purposes, are shown slightly in front of the first fin2102, with the first fin 2102 in the background, where the dashed linesrepresent areas covered from the front view. Epitaxial N-type source ordrain regions 2112, such as epitaxial silicon source of drainstructures, are also shown at locations of the first fin 2102 betweenthe gate locations 2108 and 2110. Additionally, an inter-layerdielectric material 2114 is included at locations of the first fin 2102between the gate locations 2108 and 2110.

The PMOS region of the starting structure 2100 includes a second fin2122, such as a second silicon fin, which is formed above and may becontinuous with the substrate 2104. The second fin 2122 has fin ends2126 which may be formed from local or broad fin cuts. A second activegate electrode location 2128 and second dummy gate electrode locations2130 are formed over the second fin 2122 and, for the sake ofillustration purposes, are shown slightly in front of the second fin2122, with the second fin 2122 in the background, where the dashed linesrepresent areas covered from the front view. Epitaxial P-type source ordrain regions 2132, such as epitaxial silicon germanium source of drainstructures, are also shown at locations of the second fin 2122 betweenthe gate locations 2128 and 2130. Additionally, an inter-layerdielectric material 2134 is included at locations of the second fin 2122between the gate locations 2128 and 2130.

Referring to FIG. 21B, the first and second dummy gate electrodes atlocations 2110 and 2130, respectively, are removed. Upon removal, thefin ends 2106 of first fin 2102 and the fin ends 2126 of second fin 2122are exposed. The removal also creates openings 2116 and 2136,respectively, where dielectric plugs, e.g., fin end stressor dielectricplugs, may ultimately be formed.

Referring to FIG. 21C, a material liner 2140 is formed conformal withthe structure of FIG. 21B. In an embodiment, the material liner includessilicon and nitrogen, such as a silicon nitride material liner.

Referring to FIG. 21D, a protective crown layer 2142, such as a metalnitride layer, is formed on the structure of FIG. 21C.

Referring to FIG. 21E, a hardmask material 2144, such as a carbon-basedhardmask material is formed over the structure of FIG. 21D. Alithographic mask or mask stack 2146 is formed over the hardmaskmaterial 2144.

Referring to FIG. 21F, portions of the hardmask material 2144 andportions of the protective crown layer 2142 in the PMOS region areremoved from the structure of FIG. 21E. The lithographic mask or maskstack 2146 is also removed.

Referring to FIG. 21G, a second material liner 2148 is formed conformalwith the structure of FIG. 21F. In an embodiment, the second materialliner includes silicon and nitrogen, such as a second silicon nitridematerial liner. In an embodiment, the second material liner 2148 has adifferent stress state to adjust stress in exposed plugs.

Referring to FIG. 21H, a second hardmask material 2150, such as a secondcarbon-based hardmask material is formed over the structure of FIG. 21Gand is then recessed within openings 2136 of the PMOS region of thestructure.

Referring to FIG. 21I, the second material liner 2148 is etched from thestructure of FIG. 2H to remove the second material liner 2148 from theNMOS region and to recess the second material liner 2148 in the PMOSregion of the structure.

Referring to FIG. 2J, the hardmask material 2144, the protective crownlayer 2142, and the second hardmask material 2150 are removed from thestructure of FIG. 2I. The removal leaves two different fill structuresfor openings 2116 as compared to openings 2136, respectively.

Referring to FIG. 2K, an insulating fill material 2152 is formed in theopenings 2116 and 2136 of the structure of FIG. 2J and is planarized. Inan embodiment, the insulating fill material 2152 is a flowable oxidematerial, such as a flowable silicon oxide or silicon dioxide material.

Referring to FIG. 2L, the insulating fill material 2152 is recessedwithin the openings 2116 and 2136 of the structure of FIG. 2K to form arecessed insulating fill material 2154. In an embodiment, a steamoxidation process is performed as part of the recess process orsubsequent to the recess process to cure the recessed insulating fillmaterial 2154. In one such embodiment, the recessed insulating fillmaterial 2154 shrinks, inducing a tensile stress on the fins 2102 and2122. However, there is relatively less tensile stress inducing materialin the PMOS region than in the NMOS region.

Referring to FIG. 21M, a third material liner 2156 is over the structureof FIG. 21L. In an embodiment, the third material liner 2156 includessilicon and nitrogen, such as a third silicon nitride material liner. Inan embodiment, the third material liner 2156 prevents recessedinsulating fill material 2154 from being etched out during a subsequentsource or drain contact etch.

FIGS. 22A-22D illustrate cross-sectional views of exemplary structuresof a PMOS fin end stressor dielectric plug, in accordance with anembodiment of the present disclosure.

Referring to FIG. 22A, an opening 2136 on the PMOS region of structure2100 includes a material liner 2140 along the sidewalls of the opening2136. A second material liner 2148 is conformal with a lower portion ofthe material liner 2140 but is recessed relative to an upper portion ofthe material liner 2140. A recessed insulating fill material 2154 iswithin the second material liner 2148 and has an upper surface co-planarwith an upper surface of the second material liner 2148. A thirdmaterial liner 2156 is within the upper portion of the material liner2140 and is on the upper surface of the insulating fill material 2154and on the upper surface of the second material liner 2148. The thirdmaterial liner 2156 has a seam 2157, e.g., as an artifact of adeposition process used to form the third material liner 2156.

Referring to FIG. 22B, an opening 2136 on the PMOS region of structure2100 includes a material liner 2140 along the sidewalls of the opening2136. A second material liner 2148 is conformal with a lower portion ofthe material liner 2140 but is recessed relative to an upper portion ofthe material liner 2140. A recessed insulating fill material 2154 iswithin the second material liner 2148 and has an upper surface co-planarwith an upper surface of the second material liner 2148. A thirdmaterial liner 2156 is within the upper portion of the material liner2140 and is on the upper surface of the insulating fill material 2154and on the upper surface of the second material liner 2148. The thirdmaterial liner 2156 does not have a seam.

Referring to FIG. 22C, an opening 2136 on the PMOS region of structure2100 includes a material liner 2140 along the sidewalls of the opening2136. A second material liner 2148 is conformal with a lower portion ofthe material liner 2140 but is recessed relative to an upper portion ofthe material liner 2140. A recessed insulating fill material 2154 iswithin and over the second material liner 2148 and has an upper surfaceabove an upper surface of the second material liner 2148. A thirdmaterial liner 2156 is within the upper portion of the material liner2140 and is on the upper surface of the insulating fill material 2154.The third material liner 2156 is shown without a seam, but in otherembodiments, the third material liner 2156 has a seam.

Referring to FIG. 22D, an opening 2136 on the PMOS region of structure2100 includes a material liner 2140 along the sidewalls of the opening2136. A second material liner 2148 is conformal with a lower portion ofthe material liner 2140 but is recessed relative to an upper portion ofthe material liner 2140. A recessed insulating fill material 2154 iswithin the second material liner 2148 and has an upper surface recessedbelow an upper surface of the second material liner 2148. A thirdmaterial liner 2156 is within the upper portion of the material liner2140 and is on the upper surface of the insulating fill material 2154and on the upper surface of the second material liner 2148. The thirdmaterial liner 2156 is shown without a seam, but in other embodiments,the third material liner 2156 has a seam.

Referring collectively to FIGS. 19A, 19B, 20A, 20B, 21A-21M, and22A-22D, in accordance with an embodiment of the present disclosure, anintegrated circuit structure includes a fin, such as a silicon, the finhaving a top and sidewalls. The top has a longest dimension along adirection. A first isolation structure is over a first end of the fin. Agate structure includes a gate electrode over the top of and laterallyadjacent to the sidewalls of a region of the fin. The gate structure isspaced apart from the first isolation structure along the direction. Asecond isolation structure is over a second end of the fin, the secondend opposite the first end. The second isolation structure is spacedapart from the gate structure along the direction. The first isolationstructure and the second isolation structure both include a firstdielectric material (e.g., material liner 2140) laterally surrounding arecessed second dielectric material (e.g., second material liner 2148)distinct from the first dielectric material. The recessed seconddielectric material is laterally surrounding at least a portion of athird dielectric material (e.g., recessed insulating fill material 2154)different from the first and second dielectric materials.

In one embodiment, the first isolation structure and the secondisolation structure both further include a fourth dielectric material(e.g., third material liner 2156) laterally surrounded by an upperportion of the first dielectric material, the fourth dielectric materialon an upper surface of the third dielectric material. In one suchembodiment, the fourth dielectric material is further on an uppersurface of the second dielectric material. In another such embodiment,the fourth dielectric material has an approximately vertical centralseam. In another such embodiment, the fourth dielectric material doesnot have a seam.

In one embodiment, the third dielectric material has an upper surfaceco-planar with an upper surface of the second dielectric material. Inone embodiment, the third dielectric material has an upper surface belowan upper surface of the second dielectric material. In one embodiment,the third dielectric material has an upper surface above an uppersurface of the second dielectric material, and the third dielectricmaterial is further over the upper surface of the second dielectricmaterial. In one embodiment, the first and second isolation structuresinduce a compressive stress on the fin. In one such embodiment, the gateelectrode is a P-type gate electrode.

In one embodiment, the first isolation structure has a width along thedirection, the gate structure has the width along the direction, and thesecond isolation structure has the width along the direction. In onesuch embodiment, a center of the gate structure is spaced apart from acenter of the first isolation structure by a pitch along the direction,and a center of the second isolation structure is spaced apart from thecenter of the gate structure by the pitch along the direction. In oneembodiment, the first and second isolation structures are both in acorresponding trench in an inter-layer dielectric layer.

In one such embodiment, a first source or drain region is between thegate structure and the first isolation structure. A second source ordrain region is between the gate structure and the second isolationstructure. In one such embodiment, the first and second source or drainregions are embedded source or drain regions including silicon andgermanium. In one such embodiment, the gate structure further includes ahigh-k dielectric layer between the gate electrode and the fin and alongsidewalls of the gate electrode.

In another aspect, the depth of individual dielectric plugs may bevaried within a semiconductor structure or within an architecture formedon a common substrate. As an example, FIG. 23A illustrates across-sectional view of another semiconductor structure having fin-endstress-inducing features, in accordance with another embodiment of thepresent disclosure. Referring to FIG. 23A, a shallow dielectric plug2308A is included along with a pair of deep dielectric plugs 2308B and2308C. In one such embodiment, as depicted, the shallow dielectric plug2308C is at a depth approximately equal to the depth of a semiconductorfin 2302 within a substrate 2304, while the pair of deep dielectricplugs 2308B and 2308C is at a depth below the depth of the semiconductorfin 2302 within substrate 2304.

Referring again to FIG. 23A, such an arrangement may enable stressamplification on fin trim isolation (FTI) devices in a trench thatetches deeper into the substrate 2304 in order to provide isolationbetween adjacent fins 2302. Such an approach may be implemented toincreases the density of transistors on a chip. In an embodiment, thestress effect induced on transistors from the plug fill is magnified inFTI transistors since the stress transfer occurs in both the fin and ina substrate or well underneath the transistor.

In another aspect, the width or amount of a tensile stress-inducingoxide layer included in a dielectric plug may be varied within asemiconductor structure or within an architecture formed on a commonsubstrate, e.g., depending if the device is a PMOS device or an NMOSdevice. As an example, FIG. 23B illustrates a cross-sectional view ofanother semiconductor structure having fin-end stress-inducing features,in accordance with another embodiment of the present disclosure.Referring to FIG. 23B, in a particular embodiment, NMOS devices includerelatively more of a tensile stress-inducing oxide layer 2350 thancorresponding PMOS devices.

With reference again to FIG. 23B, in an embodiment, differentiating plugfill is implemented to induce appropriate stress in NMOS and PMOS. Forexample, NMOS plugs 2308D and 2308E have a greater volume and greaterwidth of the tensile stress-inducing oxide layer 2350 than do PMOS plugs2308F and 2308G. The plug fill may be patterned to induce differentstress in NMOS and PMOS devices. For example, lithographic patterningmay be used to open up PMOS devices (e.g., widen the dielectric plugtrenches for PMOS devices), at which point different fill options can beperformed to differentiate the plug fill in NMOS versus PMOS devices. Inan exemplary embodiment, reducing the volume of a flowable oxide in theplug on PMOS devices can reduce the induced tensile stress. In one suchembodiment, compressive stress may be dominate, e.g., from compressivelystressing source and drain regions. In other embodiments, the use ofdifferent plug liners or different fill materials provides tunablestress control.

As described above, it is to be appreciated that poly plug stresseffects can benefit both NMOS transistors (e.g., tensile channel stress)and PMOS transistors (e.g., compressive channel stress). In accordancewith an embodiment of the present disclosure, a semiconductor fin is auniaxially stressed semiconductor fin. The uniaxially stressedsemiconductor fin may be uniaxially stressed with tensile stress or withcompressive stress. For example, FIG. 24A illustrates an angled view ofa fin having tensile uniaxial stress, while FIG. 24B illustrates anangled view of a fin having compressive uniaxial stress, in accordancewith one or more embodiments of the present disclosure.

Referring to FIG. 24A, a semiconductor fin 2400 has a discrete channelregion (C) disposed therein. A source region (S) and a drain region (D)are disposed in the semiconductor fin 2400, on either side of thechannel region (C). The discrete channel region of the semiconductor fin2400 has a current flow direction along the direction of a uniaxialtensile stress (arrows pointed away from one another and towards ends2402 and 2404), from the source region (S) to the drain region (D).

Referring to FIG. 24B, a semiconductor fin 2450 has a discrete channelregion (C) disposed therein. A source region (S) and a drain region (D)are disposed in the semiconductor fin 2450, on either side of thechannel region (C). The discrete channel region of the semiconductor fin2450 has a current flow direction along the direction of a uniaxialcompressive stress (arrows pointed toward one another and from ends 2452and 2454), from the source region (S) to the drain region (D).Accordingly, embodiments described herein may be implemented to improvetransistor mobility and drive current, allowing for faster performingcircuits and chips.

In another aspect, there may be a relationship between locations wheregate line cuts (poly cuts) are made and fin-trim isolation (FTI) localfin cuts are made. In an embodiment, FTI local fin cuts are made only inlocations where poly cuts are made. In one such embodiment, however, anFTI cut is not necessarily made at every location where a poly cut ismade.

FIGS. 25A and 25B illustrate plan views representing various operationsin a method of patterning of fins with single gate spacing for forming alocal isolation structure in select gate line cut locations, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 25A, a method of fabricating an integrated circuitstructure includes forming a plurality of fins 2502, individual ones ofthe plurality of fins 2502 having a longest dimension along a firstdirection 2504. A plurality of gate structures 2506 is over theplurality of fins 2502, individual ones of the gate structures 2506having a longest dimension along a second direction 2508 orthogonal tothe first direction 2504. In an embodiment, the gate structures 2506 aresacrificial or dummy gate lines, e.g., fabricated from polycrystallinesilicon. In one embodiment, the plurality of fins 2502 are silicon finsand are continuous with a portion of an underlying silicon substrate.

Referring again to FIG. 25A, a dielectric material structure 2510 isformed between adjacent ones of the plurality of gate structures 2506.Portions 2512 and 2513 of two of the plurality of gate structures 2506are removed to expose portions of each of the plurality of fins 2502. Inan embodiment, removing the portions 2512 and 2513 of the two of thegate structures 2506 involves using a lithographic window wider than awidth of each of the portions 2512 and 2513 of the gate structures 2506.The exposed portion of each of the plurality of fins 2502 at location2512 is removed to form a cut region 2520. In an embodiment, the exposedportion of each of the plurality of fins 2502 is removed using a dry orplasma etch process. However, the exposed portion of each of theplurality of fins 2502 at location 2513 is masked from removal. In anembodiment, the region 2512/2520 represents both a poly cut and an FTIlocal fin cut. However, the location 2513 represents a poly cut only.

Referring to FIG. 25B, the location 2512/2520 of the poly cut and FTIlocal fin cut and the location 2513 of the poly cut are filled withinsulating structures 2530 such as a dielectric plugs. Exemplaryinsulating structures or “poly cut” or “plug” structure are describedbelow.

FIGS. 26A-26C illustrate cross-sectional views of various possibilitiesfor dielectric plugs for poly cut and FTI local fin cut locations andpoly cut only locations for various regions of the structure of FIG.25B, in accordance with an embodiment of the present disclosure.

Referring to FIG. 26A, a cross-sectional view of a portion 2600A of thedielectric plug 2530 at location 2513 is shown along the a-a′ axis ofthe structure of FIG. 25B. The portion 2600A of the dielectric plug 2530is shown on an uncut fin 2502 and between dielectric material structures2510.

Referring to FIG. 26B, a cross-sectional view of a portion 2600B of thedielectric plug 2530 at location 2512 is shown along the b-b′ axis ofthe structure of FIG. 25B. The portion 2600B of the dielectric plug 2530is shown on an cut fin location 2520 and between dielectric materialstructures 2510.

Referring to FIG. 26C, a cross-sectional view of a portion 2600C of thedielectric plug 2530 at location 2512 is shown along the c-c′ axis ofthe structure of FIG. 25B. The portion 2600C of the dielectric plug 2530is shown on a trench isolation structure 2602 between fins 2502 andbetween dielectric material structures 2510. In an embodiment, examplesof which are described above, the trench isolation structure 2602includes a first insulating layer 2602A, a second insulating layer2602B, and an insulating fill material 2602C on the second insulatinglayer 2602B.

Referring collectively to FIGS. 25A, 25B and 26A-26C, in accordance withan embodiment of the present disclosure, a method of fabricating anintegrated circuit structure includes forming a plurality of fins,individual ones of the plurality of fins along a first direction. Aplurality of gate structures is formed over the plurality of fins,individual ones of the gate structures along a second directionorthogonal to the first direction. A dielectric material structure isformed between adjacent ones of the plurality of gate structures. Aportion of a first of the plurality of gate structures is removed toexpose a first portion of each of the plurality of fins. A portion of asecond of the plurality of gate structures is removed to expose a secondportion of each of the plurality of fins. The exposed first portion ofeach of the plurality of fins is removed, but the exposed second portionof each of the plurality of fins is not removed. A first insulatingstructure is formed in a location of the removed first portion of theplurality of fins. A second insulating structure is formed in a locationof the removed portion of the second of the plurality of gatestructures.

In one embodiment, removing the portions of the first and second of theplurality of gate structures involves using a lithographic window widerthan a width of each of the portions of the first and second of theplurality of gate structures. In one embodiment, removing the exposedfirst portion of each of the plurality of fins involves etching to adepth less than a height of the plurality of fins. In one suchembodiment, the depth is greater than a depth of source or drain regionsin the plurality of fins. In one embodiment, the plurality of finsinclude silicon and are continuous with a portion of a siliconsubstrate.

Referring collectively to FIGS. 16A, 25A, 25B and 26A-26C, in accordancewith another embodiment of the present disclosure, an integrated circuitstructure includes a fin including silicon, the fin having a longestdimension along a first direction. An isolation structure is over anupper portion of the fin, the isolation structure having a center alongthe first direction. A first gate structure is over the upper portion ofthe fin, the first gate structure having a longest dimension along asecond direction orthogonal to the first direction. A center of thefirst gate structure is spaced apart from the center of the isolationstructure by a pitch along the first direction. A second gate structureis over the upper portion of the fin, the second gate structure having alongest dimension along the second direction. A center of the secondgate structure is spaced apart from the center of the first gatestructure by the pitch along the first direction. A third gate structureis over the upper portion of the fin opposite a side of the isolationstructure from the first and second gate structures, the third gatestructure having a longest dimension along the second direction. Acenter of the third gate structure is spaced apart from the center ofthe isolation structure by the pitch along the first direction.

In one embodiment, each of the first gate structure, the second gatestructure and the third gate structure includes a gate electrode on andbetween sidewalls of a high-k gate dielectric layer. In one suchembodiment, each of the first gate structure, the second gate structureand the third gate structure further includes an insulating cap on thegate electrode and on and the sidewalls of the high-k gate dielectriclayer.

In one embodiment, a first epitaxial semiconductor region is on theupper portion of the fin between the first gate structure and theisolation structure. A second epitaxial semiconductor region is on theupper portion of the fin between the first gate structure and the secondgate structure. A third epitaxial semiconductor region on the upperportion of the fin between the third gate structure and the isolationstructure. In one such embodiment, the first, second and third epitaxialsemiconductor regions include silicon and germanium. In another suchembodiment, the first, second and third epitaxial semiconductor regionsincludes silicon.

Referring collectively to FIGS. 16A, 25A, 25B and 26A-26C, in accordancewith another embodiment of the present disclosure, an integrated circuitstructure includes a shallow trench isolation (STI) structure between apair of semiconductor fins, the STI structure having a longest dimensionalong a first direction. An isolation structure is on the STI structure,the isolation structure having a center along the first direction. Afirst gate structure on the STI structure, the first gate structurehaving a longest dimension along a second direction orthogonal to thefirst direction. A center of the first gate structure is spaced apartfrom the center of the isolation structure by a pitch along the firstdirection. A second gate structure is on the STI structure, the secondgate structure having a longest dimension along the second direction. Acenter of the second gate structure is spaced apart from the center ofthe first gate structure by the pitch along the first direction. A thirdgate structure is on the STI structure opposite a side of the isolationstructure from the first and second gate structures, the third gatestructure having a longest dimension along the second direction. Acenter of the third gate structure is spaced apart from the center ofthe isolation structure by the pitch along the first direction.

In one embodiment, each of the first gate structure, the second gatestructure and the third gate structure includes a gate electrode on andbetween sidewalls of a high-k gate dielectric layer. In one suchembodiment, each of the first gate structure, the second gate structureand the third gate structure further includes an insulating cap on thegate electrode and on and the sidewalls of the high-k gate dielectriclayer. In one embodiment, the pair of semiconductor fins is a pair ofsilicon fins.

In another aspect, whether a poly cut and FTI local fin cut together ora poly cut only, the insulating structures or dielectric plugs used tofill the cut locations may laterally extend into dielectric spacers ofthe corresponding cut gate line, or even beyond the dielectric spacersof the corresponding cut gate line.

In a first example where trench contact shape is not affected by a polycut dielectric plug, FIG. 27A illustrates a plan view and correspondingcross-sectional view of an integrated circuit structure having a gateline cut with a dielectric plug that extends into dielectric spacers ofthe gate line, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 27A, an integrated circuit structure 2700A includes afirst silicon fin 2702 having a longest dimension along a firstdirection 2703. A second silicon fin 2704 has a longest dimension alongthe first direction 2703. An insulator material 2706 is between thefirst silicon fin 2702 and the second silicon fin 2704. A gate line 2708is over the first silicon fin 2702 and over the second silicon fin 2704along a second direction 2709, the second direction 2709 orthogonal tothe first direction 2703. The gate line 2708 has a first side 2708A anda second side 2708B, and has a first end 2708C and a second end 2708D.The gate line 2708 has a discontinuity 2710 over the insulator material2706, between the first end 2708C and the second end 2708D of the gateline 2708. The discontinuity 2710 is filled by a dielectric plug 2712.

A trench contact 2714 is over the first silicon fin 2702 and over thesecond silicon fin 2704 along the second direction 2709 at the firstside 2708A of the gate line 2708. The trench contact 2714 is continuousover the insulator material 2706 at a location 2715 laterally adjacentto the dielectric plug 2712. A dielectric spacer 2716 is laterallybetween the trench contact 2714 and the first side 2708A of the gateline 2708. The dielectric spacer 2716 is continuous along the first side2708A of the gate line 2708 and the dielectric plug 2712. The dielectricspacer 2716 has a width (W2) laterally adjacent to the dielectric plug2712 thinner than a width (W1) laterally adjacent to the first side2708A of the gate line 2708.

In one embodiment, a second trench contact 2718 is over the firstsilicon fin 2702 and over the second silicon fin 2704 along the seconddirection 2709 at the second side 2708B of the gate line 2708. Thesecond trench contact 2718 is continuous over the insulator material2706 at a location 2719 laterally adjacent to the dielectric plug 2712.In one such embodiment, a second dielectric spacer 2720 is laterallybetween the second trench contact 2718 and the second side 2708B of thegate line 2708. The second dielectric spacer 2720 is continuous alongthe second side 2708B of the gate line 2708 and the dielectric plug2712. The second dielectric spacer has a width laterally adjacent to thedielectric 2712 plug thinner than a width laterally adjacent to thesecond side 2708B of the gate line 2708.

In one embodiment, the gate line 2708 includes a high-k gate dielectriclayer 2722, a gate electrode 2724, and a dielectric cap layer 2726. Inone embodiment, the dielectric plug 2712 includes a same material as thedielectric spacer 2714 but is discrete from the dielectric spacer 2714.In one embodiment, the dielectric plug 2712 includes a differentmaterial than the dielectric spacer 2714.

In a second example where trench contact shape is affected by a poly cutdielectric plug, FIG. 27B illustrates a plan view and correspondingcross-sectional view of an integrated circuit structure having a gateline cut with a dielectric plug that extends beyond dielectric spacersof the gate line, in accordance with another embodiment of the presentdisclosure.

Referring to FIG. 27B, an integrated circuit structure 2700B includes afirst silicon fin 2752 having a longest dimension along a firstdirection 2753. A second silicon fin 2754 has a longest dimension alongthe first direction 2753. An insulator material 2756 is between thefirst silicon fin 2752 and the second silicon fin 2754. A gate line 2758is over the first silicon fin 2752 and over the second silicon fin 2754along a second direction 2759, the second direction 2759 orthogonal tothe first direction 2753. The gate line 2758 has a first side 2758A anda second side 2758B, and has a first end 2758C and a second end 2758D.The gate line 2758 has a discontinuity 2760 over the insulator material2756, between the first end 2758C and the second end 2758D of the gateline 2758. The discontinuity 2760 is filled by a dielectric plug 2762.

A trench contact 2764 is over the first silicon fin 2752 and over thesecond silicon fin 2754 along the second direction 2759 at the firstside 2758A of the gate line 2758. The trench contact 2764 is continuousover the insulator material 2756 at a location 2765 laterally adjacentto the dielectric plug 2762. A dielectric spacer 2766 is laterallybetween the trench contact 2764 and the first side 2758A of the gateline 2758. The dielectric spacer 2766 is along the first side 2758A ofthe gate line 2758 but is not along the dielectric plug 2762, resultingin a discontinuous dielectric spacer 2766. The trench contact 2764 has awidth (W1) laterally adjacent to the dielectric plug 2762 that isthinner than a width (W2) laterally adjacent to the dielectric spacer2766.

In one embodiment, a second trench contact 2768 is over the firstsilicon fin 2752 and over the second silicon fin 2754 along the seconddirection 2759 at the second side 2758B of the gate line 2758. Thesecond trench contact 2768 is continuous over the insulator material2756 at a location 2769 laterally adjacent to the dielectric plug 2762.In one such embodiment, a second dielectric spacer 2770 is laterallybetween the second trench contact 2768 and the second side 2758B of thegate line 2758. The second dielectric spacer 2770 is along the secondside 2508B of the gate line 2758 but is not along the dielectric plug2762, resulting in a discontinuous dielectric spacer 2770. The secondtrench contact 2768 has a width laterally adjacent to the dielectricplug 2762 thinner than a width laterally adjacent to the seconddielectric spacer 2770.

In one embodiment, the gate line 2758 includes a high-k gate dielectriclayer 2772, a gate electrode 2774, and a dielectric cap layer 2776. Inone embodiment, the dielectric plug 2762 includes a same material as thedielectric spacer 2764 but is discrete from the dielectric spacer 2764.In one embodiment, the dielectric plug 2762 includes a differentmaterial than the dielectric spacer 2764.

In a third example where a dielectric plug for a poly cut locationtapers from the top of the plug to the bottom of the plug, FIGS. 28A-28Fillustrate cross-sectional views of various operations in a method offabricating an integrated circuit structure having a gate line cut witha dielectric plug with an upper portion that extends beyond dielectricspacers of the gate line and a lower portion that extends into thedielectric spacers of the gate line, in accordance with anotherembodiment of the present disclosure.

Referring to FIG. 28A, a plurality of gate lines 2802 is formed over astructure 2804, such as over a trench isolation structure betweensemiconductor fins. In one embodiment, each of the gate lines 2802 is asacrificial or dummy gate line, e.g., with a dummy gate electrode 2806and a dielectric cap 2808. Portions of such sacrificial or dummy gatelines may later replaced in a replacement gate process, e.g., subsequentto the below described dielectric plug formation. Dielectric spacers2810 are along sidewalls of the gate lines 2802. A dielectric material2812, such as an inter-dielectric layer, is between the gate lines 2802.A mask 2814 is formed and lithographically patterned to expose a portionof one of the gate lines 2802.

Referring to FIG. 28B, with the mask 2814 in place, the center gate line2802 is removed with an etch process. The mask 2814 is then removed. Inan embodiment, the etch process erodes portions of the dielectricspacers 2810 of the removed gate line 2802, forming reduced dielectricspacers 2816. Additionally, upper portions of the dielectric material2812 exposed by the mask 2814 are eroded in the etch process, formingeroded dielectric material portions 2818. In a particular embodiment,residual dummy gate material 2820, such as residual polycrystallinesilicon, remains in the structure, as an artifact of an incomplete etchprocess.

Referring to FIG. 28C, a hardmask 2822 is formed over the structure ofFIG. 28B. The hardmask 2822 may be conformal with the upper portion ofthe structure of FIG. 2B and, in particular, with the eroded dielectricmaterial portions 2818.

Referring to FIG. 28D, the residual dummy gate material 2820 is removed,e.g., with an etch process, which may be similar in chemistry to theetch process used to remove the central one of the gate lines 2802. Inan embodiment, the hardmask 2822 protects the eroded dielectric materialportions 2818 from further erosion during the removal of the residualdummy gate material 2820.

Referring to FIG. 28E, hardmask 2822 is removed. In one embodiment,hardmask 2822 is removed without or essentially without further erosionof the eroded dielectric material portions 2818.

Referring to FIG. 28F, a dielectric plug 2830 is formed in the openingof the structure of FIG. 28E. The upper portion of dielectric plug 2830is over the eroded dielectric material portions 2818, e.g., effectivelybeyond original spacers 2810. The lower portion of dielectric plug 2830is adjacent to the reduced dielectric spacers 2816, e.g., effectivelyinto but not beyond the original spacers 2810. As a result, dielectricplug 2830 has a tapered profile as depicted in FIG. 28F. It is to beappreciated that dielectric plug 2830 may be fabricated from materialsand process described above for other poly cut or FTI plugs or fin endstressors.

In another aspect, portions of a placeholder gate structure or dummygate structure may be retained over trench isolation regions beneath apermanent gate structure as a protection against erosion of the trenchisolation regions during a replacement gate process. For example, FIGS.29A-29C illustrate a plan view and corresponding cross-sectional viewsof an integrated circuit structure having residual dummy gate materialat portions of the bottom of a permanent gate stack, in accordance withan embodiment of the present disclosure.

Referring to FIGS. 29A-29C, an integrated circuit structure includes afin 2902, such as a silicon fin, protruding from a semiconductorsubstrate 2904. The fin 2902 has a lower fin portion 2902B and an upperfin portion 2902A. The upper fin portion 2902A has a top 2902C andsidewalls 2902D. An isolation structure 2906 surrounds the lower finportion 2902B. The isolation structure 2906 includes an insulatingmaterial 2906C having a top surface 2907. A semiconductor material 2908is on a portion of the top surface 2907 of the insulating material2906C. The semiconductor material 2908 is separated from the fin 2902.

A gate dielectric layer 2910 is over the top 2902C of the upper finportion 2902A and laterally adjacent the sidewalls 2902D of the upperfin portion 2902A. The gate dielectric layer 2910 is further on thesemiconductor material 2908 on the portion of the top surface 2907 ofthe insulating material 2906C. An intervening additional gate dielectriclayer 2911, such as an oxidized portion of the fin 2902 may be betweenthe gate dielectric layer 2910 over the top 2902C of the upper finportion 2902A and laterally adjacent the sidewalls 2902D of the upperfin portion 2902A. A gate electrode 2912 is over the gate dielectriclayer 2910 over the top 2902C of the upper fin portion 2902A andlaterally adjacent the sidewalls 2902D of the upper fin portion 2902A.The gate electrode 2912 is further over the gate dielectric layer 2910on the semiconductor material 2908 on the portion of the top surface2907 of the insulating material 2906C. A first source or drain region2916 is adjacent a first side of the gate electrode 2912, and a secondsource or drain region 2918 is adjacent a second side of the gateelectrode 2912, the second side opposite the first side. In anembodiment, examples of which are described above, the isolationstructure 2906 includes a first insulating layer 2906A, a secondinsulating layer 2906B, and the insulating material 2906C.

In one embodiment, the semiconductor material 2908 on the portion of thetop surface 2907 of the insulating material 2906C is or includespolycrystalline silicon. In one embodiment, the top surface 2907 of theinsulating material 2906C has a concave depression, and is depicted, andthe semiconductor material 2908 is in the concave depression. In oneembodiment, the isolation structure 2906 includes a second insulatingmaterial (2906A or 2906B or both 2906A/2906B) along a bottom andsidewalls of the insulating material 2906C. In one such embodiment, theportion of the second insulating material (2906A or 2906B or both2906A/2906B) along the sidewalls of the insulating material 2906C has atop surface above an uppermost surface of the insulating material 2906C,as is depicted. In one embodiment, the top surface of the secondinsulating material (2906A or 2906B or both 2906A/2906B) is above orco-planar with an uppermost surface of the semiconductor material 2908.

In one embodiment, the semiconductor material 2908 on the portion of thetop surface 2907 of the insulating material 2906C does not extend beyondthe gate dielectric layer 2910. That is, from a plan view perspective,the location of the semiconductor material 2908 is limited to the regioncovered by the gate stack 2912/2910. In one embodiment, a firstdielectric spacer 2920 is along the first side of the gate electrode2912. A second dielectric spacer 2922 is along the second side of thegate electrode 2912. In one such embodiment, the gate dielectric layer2910 further extends along sidewalls of the first dielectric spacer 2920and the second dielectric spacer 2922, as is depicted in FIG. 29B.

In one embodiment, the gate electrode 2912 includes a conformalconductive layer 2912A (e.g., a workfunction layer). In one suchembodiment, the workfunction layer 2912A includes titanium and nitrogen.In another embodiment, the workfunction layer 2912A includes titanium,aluminum, carbon and nitrogen. In one embodiment, the gate electrode2912 further includes a conductive fill metal layer 2912B over theworkfunction layer 2912A. In one such embodiment, the conductive fillmetal layer 2912B includes tungsten. In a particular embodiment, theconductive fill metal layer 2912B includes 95 or greater atomic percenttungsten and 0.1 to 2 atomic percent fluorine. In one embodiment, aninsulating cap 2924 is on the gate electrode 2912 and may extend overthe gate dielectric layer 2910, as is depicted in FIG. 29B.

FIGS. 30A-30D illustrate cross-sectional views of various operations ina method of fabricating an integrated circuit structure having residualdummy gate material at portions of the bottom of a permanent gate stack,in accordance with another embodiment of the present disclosure. Theperspective show is along a portion of the a-a′ axis of the structure ofFIG. 29C.

Referring to FIG. 30A, a method of fabricating an integrated circuitstructure includes forming a fin 3000 from a semiconductor substrate3002. The fin 3000 has a lower fin portion 3000A and an upper finportion 3000B. The upper fin portion 3000B has a top 3000C and sidewalls3000D. An isolation structure 3004 surrounds the lower fin portion3000A. The isolation structure 3004 includes an insulating material3004C having a top surface 3005. A placeholder gate electrode 3006 isover the top 3000C of the upper fin portion 3000B and laterally adjacentthe sidewalls 3000D of the upper fin portion 3000B. The placeholder gateelectrode 3006 includes a semiconductor material.

Although not depicted from the perspective of FIG. 30A (but locationsfor which are shown in FIG. 29C), a first source or drain region may beformed adjacent a first side of the placeholder gate electrode 3006, anda second source or drain region may be formed adjacent a second side ofthe placeholder gate electrode 3006, the second side opposite the firstside. Additionally, gate dielectric spacers may be formed along thesidewalls of the placeholder gate electrode 3006, and an inter-layerdielectric (ILD) layer may be formed laterally adjacent the placeholdergate electrode 3006.

In one embodiment, the placeholder gate electrode 3006 is or includespolycrystalline silicon. In one embodiment, the top surface 3005 of theinsulating material 3004C of the isolation structure 3004 has a concavedepression, as is depicted. A portion of the placeholder gate electrode3006 is in the concave depression. In one embodiment, the isolationstructure 3004 includes a second insulating material (3004A or 3004B orboth 3004A and 3004B) is along a bottom and sidewalls of the insulatingmaterial 3004C, as is depicted. In one such embodiment, the portion ofthe second insulating material (3004A or 3004B or both 3004A and 3004B)along the sidewalls of the insulating material 3004C has a top surfaceabove at least a portion of the top surface 3005 of the insulatingmaterial 3004C. In one embodiment, the top surface of the secondinsulating material (3004A or 3004B or both 3004A and 3004B) is above alowermost surface of a portion of the placeholder gate electrode 3006.

Referring to FIG. 30B, the placeholder gate electrode 3006 is etchedfrom over the top 3000C and sidewalls 3000D of the upper fin portion3000B, e.g., along direction 3008 of FIG. 30A. The etch process may bereferred to as a replacement gate process. In an embodiment, the etchingor replacement gate process is incomplete and leaves a portion 3012 ofthe placeholder gate electrode 3006 on at least a portion of the topsurface 3005 of the insulating material 3004C of the isolation structure3004.

Referring to both FIGS. 30A and 30B, in an embodiment, an oxidizedportion 3010 of the upper fin portion 3000B formed prior to forming theplaceholder gate electrode 3006 is retained during the etch process, asis depicted. In another embodiment, however, a placeholder gatedielectric layer is formed prior to forming the placeholder gateelectrode 3006, and the placeholder gate dielectric layer is removedsubsequent to etching the placeholder gate electrode.

Referring to FIG. 30C, a gate dielectric layer 3014 is formed over thetop 3000C of the upper fin portion 3000B and laterally adjacent thesidewalls 3000D of the upper fin portion 3000B. In one embodiment, thegate dielectric layer 3014 is formed on the oxidized portion 3010 of theupper fin portion 3000B over the top 3000C of the upper fin portion3000B and laterally adjacent the sidewalls 3000D of the upper finportion 3000B, as is depicted. In another embodiment, the gatedielectric layer 3014 is formed directly on the upper fin portion 3000Bover the top of 3000C of the upper fin portion 3000B and laterallyadjacent the sidewalls 3000D of the upper fin portion 3000B in the casewhere the oxidized portion 3010 of the upper fin portion 3000B isremoved subsequent to etching the placeholder gate electrode. In eithercase, in an embodiment, the gate dielectric layer 3014 is further formedon the portion 3012 of the placeholder gate electrode 3006 on theportion of the top surface 3005 of the insulating material 3004C of theisolation structure 3004.

Referring to FIG. 30D, a permanent gate electrode 3016 is formed overthe gate dielectric layer 3014 over the top 3000C of the upper finportion 3000B and laterally adjacent the sidewalls 3000D of the upperfin portion 3000B. The permanent gate electrode 3016 is further over thegate dielectric layer 3014 on the portion 3012 of the placeholder gateelectrode 3006 on the portion of the top surface 3005 of the insulatingmaterial 3004C.

In one embodiment, forming the permanent gate electrode 3016 includesforming a workfunction layer 3016A. In one such embodiment, theworkfunction layer 3016A includes titanium and nitrogen. In another suchembodiment, the workfunction layer 3016A includes titanium, aluminum,carbon and nitrogen. In one embodiment, forming the permanent gateelectrode 3016 further includes forming a conductive fill metal layer3016B formed over the workfunction layer 3016A. In one such embodiment,forming the conductive fill metal layer 3016B includes forming atungsten-containing film using atomic layer deposition (ALD) with atungsten hexafluoride (WF₆) precursor. In an embodiment, an insulatinggate cap layer 3018 is formed on the permanent gate electrode 3016.

In another aspect, some embodiments of the present disclosure include anamorphous high-k layer in a gate dielectric structure for a gateelectrode. In other embodiments, a partially or fully crystalline high-klayer is included in a gate dielectric structure for a gate electrode.In one embodiment where a partially or fully crystalline high-k layer isincluded, the gate dielectric structure is a ferroelectric (FE) gatedielectric structure. In another embodiment where a partially or fullycrystalline high-k layer is included, the gate dielectric structure isan antiferroelectric (AFE) gate dielectric structure.

In an embodiment, approaches are described herein to increase charge ina device channel and improve sub-threshold behavior by adoptingferroelectric or antiferroelectric gate oxides. Ferroelectric andantiferroelectric gate oxide can increase channel charge for highercurrent and also can make steeper turn-on behavior.

To provide context, hafnium or zirconium (Hf or Zr) based ferroelectricand antiferroelectric (FE or AFE) materials are typically much thinnerthan ferroelectric material such lead zirconium titanate (PZT) and, assuch, may be compatible with highly scaled logic technology. There aretwo features of FE or AFE materials can improve the performance of logictransistors: (1) the higher charge in the channel achieved by FE or AFEpolarization and (2) a steeper turn-on behavior due to a sharp FE or AFEtransition. Such properties can improve the transistor performance byincreasing current and reducing subthreshold swing (SS).

FIG. 31A illustrates a cross-sectional view of a semiconductor devicehaving a ferroelectric or antiferroelectric gate dielectric structure,in accordance with an embodiment of the present disclosure.

Referring to FIG. 31A, an integrated circuit structure 3100 includes agate structure 3102 above a substrate 3104. In one embodiment, the gatestructure 3102 is above or over a semiconductor channel structure 3106including a monocrystalline material, such as monocrystalline silicon.The gate structure 3102 includes a gate dielectric over thesemiconductor channel structure 3106 and a gate electrode over the gatedielectric structure. The gate dielectric includes a ferroelectric orantiferroelectric polycrystalline material layer 3102A. The gateelectrode has a conductive layer 3102B on the ferroelectric orantiferroelectric polycrystalline material layer 3102A. The conductivelayer 3102B includes a metal and may be a barrier layer, a workfunctionlayer, or templating layer enhancing crystallization of FE or AFElayers. A gate fill layer or layer(s) 3102C is on or above theconductive layer 3102B. A source region 3108 and a drain region 3110 areon opposite sides of the gate structure 3102. Source or drain contacts3112 are electrically connected to the source region 3108 and the drainregion 3110 at locations 3149, and are spaced apart of the gatestructure 3102 by one or both of an inter-layer dielectric layer 3114 orgate dielectric spacers 3116. In the example of FIG. 31A, the sourceregion 3108 and the drain region 3110 are regions of the substrate 3104.In an embodiment, the source or drain contacts 3112 include a barrierlayer 3112A, and a conductive trench fill material 3112B. In oneembodiment, the ferroelectric or antiferroelectric polycrystallinematerial layer 3102A extends along the dielectric spacers 3116, as isdepicted in FIG. 31A.

In an embodiment, and as applicable throughout the disclosure, theferroelectric or antiferroelectric polycrystalline material layer 3102Ais a ferroelectric polycrystalline material layer. In one embodiment,the ferroelectric polycrystalline material layer is an oxide includingZr and Hf with a Zr:Hf ratio of 50:50 or greater in Zr. Theferroelectric effect may increase as the orthorhombic crystallinityincreases. In one embodiment ferroelectric polycrystalline materiallayer has at least 80% orthorhombic crystallinity.

In an embodiment, and as applicable throughout the disclosure, theferroelectric or antiferroelectric polycrystalline material layer 3102Ais an antiferroelectric polycrystalline material layer. In oneembodiment, the antiferroelectric polycrystalline material layer is anoxide including Zr and Hf with a Zr:Hf ratio of 80:20 or greater in Zr,and even up to 100% Zr, ZrO₂. In one embodiment, the antiferroelectricpolycrystalline material layer has at least 80% tetragonalcrystallinity.

In an embodiment, and as applicable throughout the disclosure, the gatedielectric of gate stack 3102 further includes an amorphous dielectriclayer 3103, such as a native silicon oxide layer, high K dielectric(HfOx, Al₂O₃, etc.), or combination of oxide and high K between theferroelectric or antiferroelectric polycrystalline material layer 3102Aand the semiconductor channel structure 3106. In an embodiment, and asapplicable throughout the disclosure, the ferroelectric orantiferroelectric polycrystalline material layer 3102A has a thicknessin the range of 1 nanometer to 8 nanometers. In an embodiment, and asapplicable throughout the disclosure, the ferroelectric orantiferroelectric polycrystalline material layer 3102A has a crystalgrain size approximately in the range of 20 or more nanometers.

In an embodiment, following deposition of the ferroelectric orantiferroelectric polycrystalline material layer 3102A, e.g., by atomiclayer deposition (ALD), a layer including a metal (e.g., layer 3102B,such as a 5-10 nanometer titanium nitride or tantalum nitride ortungsten) is formed on the ferroelectric or antiferroelectricpolycrystalline material layer 3102A. An anneal is then performed. Inone embodiment, the anneal is performed for a duration in the range of 1millisecond-30 minutes. In one embodiment, the anneal is performed at atemperature in the range of 500-1100 degrees Celsius.

FIG. 31B illustrates a cross-sectional view of another semiconductordevice having a ferroelectric or antiferroelectric gate dielectricstructure, in accordance with another embodiment of the presentdisclosure.

Referring to FIG. 31B, an integrated circuit structure 3150 includes agate structure 3152 above a substrate 3154. In one embodiment, the gatestructure 3152 is above or over a semiconductor channel structure 3156including a monocrystalline material, such as monocrystalline silicon.The gate structure 3152 includes a gate dielectric over thesemiconductor channel structure 3156 and a gate electrode over the gatedielectric structure. The gate dielectric includes a ferroelectric orantiferroelectric polycrystalline material layer 3152A, and may furtherinclude an amorphous oxide layer 3153. The gate electrode has aconductive layer 3152B on the ferroelectric or antiferroelectricpolycrystalline material layer 3152A. The conductive layer 3152Bincludes a metal and may be a barrier layer or a workfunction layer. Agate fill layer or layer(s) 3152C is on or above the conductive layer3152B. A raised source region 3158 and a raised drain region 3160, suchas regions of semiconductor material different than the semiconductorchannel structure 3156, are on opposite sides of the gate structure3152. Source or drain contacts 3162 are electrically connected to thesource region 3158 and the drain region 3160 at locations 3199, and arespaced apart of the gate structure 3152 by one or both of an inter-layerdielectric layer 3164 or gate dielectric spacers 3166. In an embodiment,the source or drain contacts 3162 include a barrier layer 3162A, and aconductive trench fill material 3162B. In one embodiment, theferroelectric or antiferroelectric polycrystalline material layer 3152Aextends along the dielectric spacers 3166, as is depicted in FIG. 31B.

FIG. 32A illustrates a plan view of a plurality of gate lines over apair of semiconductor fins, in accordance with another embodiment of thepresent disclosure.

Referring to FIG. 32A, a plurality of active gate lines 3204 is formedover a plurality of semiconductor fins 3200. Dummy gate lines 3206 areat the ends of the plurality of semiconductor fins 3200. Spacings 3208between the gate lines 3204/3206 are locations where trench contacts maybe located to provide conductive contacts to source or drain regions,such as source or drain regions 3251, 3252, 3253, and 3254. In anembodiment, the pattern of the plurality of gate lines 3204/3206 or thepattern of the plurality of semiconductor fins 3200 is described as agrating structure. In one embodiment, the grating-like pattern includesthe plurality of gate lines 3204/3206 or the pattern of the plurality ofsemiconductor fins 3200 spaced at a constant pitch and having a constantwidth, or both.

FIG. 32B illustrates a cross-sectional view, taken along the a-a′ axisof FIG. 32A, in accordance with an embodiment of the present disclosure.

Referring to FIG. 32B, a plurality of active gate lines 3264 is formedover a semiconductor fin 3262 formed above a substrate 3260. Dummy gatelines 3266 are at the ends of the semiconductor fin 3262. A dielectriclayer 3270 is outside of the dummy gate lines 3266. A trench contactmaterial 3297 is between the active gate lines 3264, and between thedummy gate lines 3266 and the active gate lines 3264. Embedded source ordrain structures 3268 are in the semiconductor fin 3262 between theactive gate lines 3264 and between the dummy gate lines 3266 and theactive gate lines 3264.

The active gate lines 3264 include a gate dielectric structure 3272, aworkfunction gate electrode portion 3274 and a fill gate electrodeportion 3276, and a dielectric capping layer 3278. Dielectric spacers3280 line the sidewalls of the active gate lines 3264 and the dummy gatelines 3266. In an embodiment, the gate dielectric structure 3272includes a ferroelectric or antiferroelectric polycrystalline materiallayer 3298. In one embodiment, the gate dielectric structure 3272further includes an amorphous oxide layer 3299.

In another aspect, devices of a same conductivity type, e.g., N-type orP-type, may have differentiated gate electrode stacks for a sameconductivity type. However, for comparison purposes, devices having asame conductivity type may have differentiated voltage threshold (VT)based on modulated doping.

FIG. 33A illustrates cross-sectional views of a pair of NMOS deviceshaving a differentiated voltage threshold based on modulated doping, anda pair of PMOS devices having a differentiated voltage threshold basedon modulated doping, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 33A, a first NMOS device 3302 is adjacent a secondNMOS device 3304 over a semiconductor active region 3300, such as over asilicon fin or substrate. Both first NMOS device 3302 and second NMOSdevice 3304 include a gate dielectric layer 3306, a first gate electrodeconductive layer 3308, such as a workfunction layer, and a gateelectrode conductive fill 3310. In an embodiment, the first gateelectrode conductive layer 3308 of the first NMOS device 3302 and of thesecond NMOS device 3304 are of a same material and a same thickness and,as such, have a same workfunction. However, the first NMOS device 3302has a lower VT than the second NMOS device 3304. In one such embodiment,the first NMOS device 3302 is referred to as a “standard VT” device, andthe second NMOS device 3304 is referred to as a “high VT” device. In anembodiment, the differentiated VT is achieved by using modulated ordifferentiated implant doping at regions 3312 of the first NMOS device3302 and the second NMOS device 3304.

Referring again to FIG. 33A, a first PMOS device 3322 is adjacent asecond PMOS device 3324 over a semiconductor active region 3320, such asover a silicon fin or substrate. Both first PMOS device 3322 and secondPMOS device 3324 include a gate dielectric layer 3326, a first gateelectrode conductive layer 3328, such as a workfunction layer, and agate electrode conductive fill 3330. In an embodiment, the first gateelectrode conductive layer 3328 of the first PMOS device 3322 and of thesecond PMOS device 3324 are of a same material and a same thickness and,as such, have a same workfunction. However, the first PMOS device 3322has a higher VT than the second PMOS device 3324. In one suchembodiment, the first PMOS device 3322 is referred to as a “standard VT”device, and the second PMOS device 3324 is referred to as a “low VT”device. In an embodiment, the differentiated VT is achieved by usingmodulated or differentiated implant doping at regions 3332 of the firstPMOS device 3322 and the second PMOS device 3324.

In contrast to FIG. 33A, FIG. 33B illustrates cross-sectional views of apair of NMOS devices having a differentiated voltage threshold based ondifferentiated gate electrode structure, and a pair of PMOS deviceshaving a differentiated voltage threshold based on differentiated gateelectrode structure, in accordance with another embodiment of thepresent disclosure.

Referring to FIG. 33B, a first NMOS device 3352 is adjacent a secondNMOS device 3354 over a semiconductor active region 3350, such as over asilicon fin or substrate. Both first NMOS device 3352 and second NMOSdevice 3354 include a gate dielectric layer 3356. However, the firstNMOS device 3352 and second NMOS device 3354 have structurally differentgate electrode stacks. In particular, the first NMOS device 3352includes a first gate electrode conductive layer 3358, such as a firstworkfunction layer, and a gate electrode conductive fill 3360. Thesecond NMOS device 3354 includes a second gate electrode conductivelayer 3359, such as a second workfunction layer, the first gateelectrode conductive layer 3358 and the gate electrode conductive fill3360. The first NMOS device 3352 has a lower VT than the second NMOSdevice 3354. In one such embodiment, the first NMOS device 3352 isreferred to as a “standard VT” device, and the second NMOS device 3354is referred to as a “high VT” device. In an embodiment, thedifferentiated VT is achieved by using differentiated gate stacks forsame conductivity type devices.

Referring again to FIG. 33B, a first PMOS device 3372 is adjacent asecond PMOS device 3374 over a semiconductor active region 3370, such asover a silicon fin or substrate. Both first PMOS device 3372 and secondPMOS device 3374 include a gate dielectric layer 3376. However, thefirst PMOS device 3372 and second PMOS device 3374 have structurallydifferent gate electrode stacks. In particular, the first PMOS device3372 includes a gate electrode conductive layer 3378A having a firstthickness, such as a workfunction layer, and a gate electrode conductivefill 3380. The second PMOS device 3374 includes a gate electrodeconductive layer 3378B having a second thickness, and the gate electrodeconductive fill 3380. In one embodiment, the gate electrode conductivelayer 3378A and the gate electrode conductive layer 3378B have a samecomposition, but the thickness of the gate electrode conductive layer3378B (second thickness) is greater than the thickness of the gateelectrode conductive layer 3378A (first thickness). The first PMOSdevice 3372 has a higher VT than the second PMOS device 3374. In onesuch embodiment, the first PMOS device 3372 is referred to as a“standard VT” device, and the second PMOS device 3374 is referred to asa “low VT” device. In an embodiment, the differentiated VT is achievedby using differentiated gate stacks for same conductivity type devices.

Referring again to FIG. 33B, in accordance with an embodiment of thepresent disclosure, an integrated circuit structure includes a fin(e.g., a silicon fin such as 3350). It is to be appreciated that the finhas a top (as shown) and sidewalls (into and out of the page). A gatedielectric layer 3356 is over the top of the fin and laterally adjacentthe sidewalls of the fin. An N-type gate electrode of device 3354 isover the gate dielectric layer 3356 over the top of the fin andlaterally adjacent the sidewalls of the fin. The N-type gate electrodeincludes a P-type metal layer 3359 on the gate dielectric layer 3356,and an N-type metal layer 3358 on the P-type metal layer 3359. As willbe appreciated, a first N-type source or drain region may be adjacent afirst side of the gate electrode (e.g., into the page), and a secondN-type source or drain region may be adjacent a second side of the gateelectrode (e.g., out of the page), the second side opposite the firstside.

In one embodiment, the P-type metal layer 3359 includes titanium andnitrogen, and the N-type metal layer 3358 includes titanium, aluminum,carbon and nitrogen. In one embodiment, the P-type metal layer 3359 hasa thickness in the range of 2-12 Angstroms, and in a specificembodiment, the P-type metal layer 3359 has a thickness in the range of2-4 Angstroms. In one embodiment, the N-type gate electrode furtherincludes a conductive fill metal layer 3360 on the N-type metal layer3358. In one such embodiment, the conductive fill metal layer 3360includes tungsten. In a particular embodiment, the conductive fill metallayer 3360 includes 95 or greater atomic percent tungsten and 0.1 to 2atomic percent fluorine.

Referring again to FIG. 33B, in accordance with another embodiment ofthe present disclosure, an integrated circuit structure includes a firstN-type device 3352 having a voltage threshold (VT), the first N-typedevice 3352 having a first gate dielectric layer 3356, and a firstN-type metal layer 3358 on the first gate dielectric layer 3356. Also,included is a second N-type device 3354 having a voltage threshold (VT),the second N-type device 3354 having a second gate dielectric layer3356, a P-type metal layer 3359 on the second gate dielectric layer3356, and a second N-type metal layer 3358 on the P-type metal layer3359.

In one embodiment, wherein the VT of the second N-type device 3354 ishigher than the VT of the first N-type device 3352. In one embodiment,the first N-type metal layer 3358 and the second N-type metal layer 3358have a same composition. In one embodiment, the first N-type metal layer3358 and the second N-type metal layer 3358 have a same thickness. Inone embodiment, wherein the N-type metal layer 3358 includes titanium,aluminum, carbon and nitrogen, and the P-type metal layer 3359 includestitanium and nitrogen.

Referring again to FIG. 33B, in accordance with another embodiment ofthe present disclosure, an integrated circuit structure includes a firstP-type device 3372 having a voltage threshold (VT), the first P-typedevice 3372 having a first gate dielectric layer 3376, and a firstP-type metal layer 3378A on the first gate dielectric layer 3376. Thefirst P-type metal layer 3378A has a thickness. A second P-type device3374 is also included and has a voltage threshold (VT). The secondP-type device 3374 has a second gate dielectric layer 3376, and a secondP-type metal layer 3378B on the second gate dielectric layer 3376. Thesecond P-type metal layer 3378B has a thickness greater than thethickness of the first P-type metal layer 3378A.

In one embodiment, the VT of the second P-type device 3374 is lower thanthe VT of the first P-type device 3372. In one embodiment, the firstP-type metal layer 3378A and the second P-type metal layer 3378B have asame composition. In one embodiment, the first P-type metal layer 3378Aand the second P-type metal layer 3378B both include titanium andnitrogen. In one embodiment, the thickness of the first P-type metallayer 3378A is less than a work-function saturation thickness of amaterial of the first P-type metal layer 3378A. In one embodiment,although not depicted the second P-type metal layer 3378B includes afirst metal film (e.g., from a second deposition) on a second metal film(e.g., from a first deposition), and a seam is between the first metalfilm and the second metal film.

Referring again to FIG. 33B, in accordance with another embodiment ofthe present disclosure, an integrated circuit structure includes a firstN-type device 3352 has a first gate dielectric layer 3356, and a firstN-type metal layer 3358 on the first gate dielectric layer 3356. Asecond N-type device 3354 has a second gate dielectric layer 3356, afirst P-type metal layer 3359 on the second gate dielectric layer 3356,and a second N-type metal layer 3358 on the first P-type metal layer3359. A first P-type device 3372 has a third gate dielectric layer 3376,and a second P-type metal layer 3378A on the third gate dielectric layer3376. The second P-type metal layer 3378A has a thickness. A secondP-type device 3374 has a fourth gate dielectric layer 3376, and a thirdP-type metal layer 3378B on the fourth gate dielectric layer 3376. Thethird P-type metal layer 3378B has a thickness greater than thethickness of the second P-type metal layer 3378A.

In one embodiment, the first N-type device 3352 has a voltage threshold(VT), the second N-type device 3354 has a voltage threshold (VT), andthe VT of the second N-type device 3354 is lower than the VT of thefirst N-type device 3352. In one embodiment, the first P-type device3372 has a voltage threshold (VT), the second P-type device 3374 has avoltage threshold (VT), and the VT of the second P-type device 3374 islower than the VT of the first P-type device 3372. In one embodiment,the third P-type metal layer 3378B includes a first metal film on asecond metal film, and a seam between the first metal film and thesecond metal film.

It is to be appreciated that greater than two types of VT devices for asame conductivity type may be included in a same structure, such as on asame die. In a first example, FIG. 34A illustrates cross-sectional viewsof a triplet of NMOS devices having a differentiated voltage thresholdbased on differentiated gate electrode structure and on modulateddoping, and a triplet of PMOS devices having a differentiated voltagethreshold based on differentiated gate electrode structure and onmodulated doping, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 34A, a first NMOS device 3402 is adjacent a secondNMOS device 3404 and a third NMOS device 3403 over a semiconductoractive region 3400, such as over a silicon fin or substrate. The firstNMOS device 3402, second NMOS device 3404, and third NMOS device 3403include a gate dielectric layer 3406. The first NMOS device 3402 andthird NMOS device 3403 have structurally same or similar gate electrodestacks. However, the second NMOS device 3404 has a structurallydifferent gate electrode stack than the first NMOS device 3402 and thethird NMOS device 3403. In particular, the first NMOS device 3402 andthe third NMOS device 3403 include a first gate electrode conductivelayer 3408, such as a first workfunction layer, and a gate electrodeconductive fill 3410. The second NMOS device 3404 includes a second gateelectrode conductive layer 3409, such as a second workfunction layer,the first gate electrode conductive layer 3408 and the gate electrodeconductive fill 3410. The first NMOS device 3402 has a lower VT than thesecond NMOS device 3404. In one such embodiment, the first NMOS device3402 is referred to as a “standard VT” device, and the second NMOSdevice 3404 is referred to as a “high VT” device. In an embodiment, thedifferentiated VT is achieved by using differentiated gate stacks forsame conductivity type devices. In an embodiment, the third NMOS device3403 has a VT different than the VT of the first NMOS device 3402 andthe second NMOS device 3404, even though the gate electrode structure ofthe third NMOS device 3403 is the same as the gate electrode structureof the first NMOS device 3402. In one embodiment, the VT of the thirdNMOS device 3403 is between the VT of the first NMOS device 3402 and thesecond NMOS device 3404. In an embodiment, the differentiated VT betweenthe third NMOS device 3403 and the first NMOS device 3402 is achieved byusing modulated or differentiated implant doping at a region 3412 of thethird NMOS device 3403. In one such embodiment, the third N-type device3403 has a channel region having a dopant concentration different than adopant concentration of a channel region of the first N-type device3402.

Referring again to FIG. 34A, a first PMOS device 3422 is adjacent asecond PMOS device 3424 and a third PMOS device 3423 over asemiconductor active region 3420, such as over a silicon fin orsubstrate. The first PMOS device 3422, second PMOS device 3424, andthird PMOS device 3423 include a gate dielectric layer 3426. The firstPMOS device 3422 and third PMOS device 3423 have structurally same orsimilar gate electrode stacks. However, the second PMOS device 3424 hasa structurally different gate electrode stack than the first PMOS device3422 and the third PMOS device 3423. In particular, the first PMOSdevice 3422 and the third PMOS device 3423 include a gate electrodeconductive layer 3428A having a first thickness, such as a workfunctionlayer, and a gate electrode conductive fill 3430. The second PMOS device3424 includes a gate electrode conductive layer 3428B having a secondthickness, and the gate electrode conductive fill 3430. In oneembodiment, the gate electrode conductive layer 3428A and the gateelectrode conductive layer 3428B have a same composition, but thethickness of the gate electrode conductive layer 3428B (secondthickness) is greater than the thickness of the gate electrodeconductive layer 3428A (first thickness). In an embodiment, the firstPMOS device 3422 has a higher VT than the second PMOS device 3424. Inone such embodiment, the first PMOS device 3422 is referred to as a“standard VT” device, and the second PMOS device 3424 is referred to asa “low VT” device. In an embodiment, the differentiated VT is achievedby using differentiated gate stacks for same conductivity type devices.In an embodiment, the third PMOS device 3423 has a VT different than theVT of the first PMOS device 3422 and the second PMOS device 3424, eventhough the gate electrode structure of the third PMOS device 3423 is thesame as the gate electrode structure of the first PMOS device 3422. Inone embodiment, the VT of the third PMOS device 3423 is between the VTof the first PMOS device 3422 and the second PMOS device 3424. In anembodiment, the differentiated VT between the third PMOS device 3423 andthe first PMOS device 3422 is achieved by using modulated ordifferentiated implant doping at a region 3432 of the third PMOS device3423. In one such embodiment, the third P-type device 3423 has a channelregion having a dopant concentration different than a dopantconcentration of a channel region of the first P-type device 3422.

In a second example, FIG. 34B illustrates cross-sectional views of atriplet of NMOS devices having a differentiated voltage threshold basedon differentiated gate electrode structure and on modulated doping, anda triplet of PMOS devices having a differentiated voltage thresholdbased on differentiated gate electrode structure and on modulateddoping, in accordance with another embodiment of the present disclosure.

Referring to FIG. 34B, a first NMOS device 3452 is adjacent a secondNMOS device 3454 and a third NMOS device 3453 over a semiconductoractive region 3450, such as over a silicon fin or substrate. The firstNMOS device 3452, second NMOS device 3454, and third NMOS device 3453include a gate dielectric layer 3456. The second NMOS device 3454 andthird NMOS device 3453 have structurally same or similar gate electrodestacks. However, the first NMOS device 3452 has a structurally differentgate electrode stack than the second NMOS device 3454 and the third NMOSdevice 3453. In particular, the first NMOS device 3452 includes a firstgate electrode conductive layer 3458, such as a first workfunctionlayer, and a gate electrode conductive fill 3460. The second NMOS device3454 and the third NMOS device 3453 include a second gate electrodeconductive layer 3459, such as a second workfunction layer, the firstgate electrode conductive layer 3458 and the gate electrode conductivefill 3460. The first NMOS device 3452 has a lower VT than the secondNMOS device 3454. In one such embodiment, the first NMOS device 3452 isreferred to as a “standard VT” device, and the second NMOS device 3454is referred to as a “high VT” device. In an embodiment, thedifferentiated VT is achieved by using differentiated gate stacks forsame conductivity type devices. In an embodiment, the third NMOS device3453 has a VT different than the VT of the first NMOS device 3452 andthe second NMOS device 3454, even though the gate electrode structure ofthe third NMOS device 3453 is the same as the gate electrode structureof the second NMOS device 3454. In one embodiment, the VT of the thirdNMOS device 3453 is between the VT of the first NMOS device 3452 and thesecond NMOS device 3454. In an embodiment, the differentiated VT betweenthe third NMOS device 3453 and the second NMOS device 3454 is achievedby using modulated or differentiated implant doping at a region 3462 ofthe third NMOS device 3453. In one such embodiment, the third N-typedevice 3453 has a channel region having a dopant concentration differentthan a dopant concentration of a channel region of the second N-typedevice 3454.

Referring again to FIG. 34B, a first PMOS device 3472 is adjacent asecond PMOS device 3474 and a third PMOS device 3473 over asemiconductor active region 3470, such as over a silicon fin orsubstrate. The first PMOS device 3472, second PMOS device 3474, andthird PMOS device 3473 include a gate dielectric layer 3476. The secondPMOS device 3474 and third PMOS device 3473 have structurally same orsimilar gate electrode stacks. However, the first PMOS device 3472 has astructurally different gate electrode stack than the second PMOS device3474 and the third PMOS device 3473. In particular, the first PMOSdevice 3472 includes a gate electrode conductive layer 3478A having afirst thickness, such as a workfunction layer, and a gate electrodeconductive fill 3480. The second PMOS device 3474 and the third PMOSdevice 3473 include a gate electrode conductive layer 3478B having asecond thickness, and the gate electrode conductive fill 3480. In oneembodiment, the gate electrode conductive layer 3478A and the gateelectrode conductive layer 3478B have a same composition, but thethickness of the gate electrode conductive layer 3478B (secondthickness) is greater than the thickness of the gate electrodeconductive layer 3478A (first thickness). In an embodiment, the firstPMOS device 3472 has a higher VT than the second PMOS device 3474. Inone such embodiment, the first PMOS device 3472 is referred to as a“standard VT” device, and the second PMOS device 3474 is referred to asa “low VT” device. In an embodiment, the differentiated VT is achievedby using differentiated gate stacks for same conductivity type devices.In an embodiment, the third PMOS device 3473 has a VT different than theVT of the first PMOS device 3472 and the second PMOS device 3474, eventhough the gate electrode structure of the third PMOS device 3473 is thesame as the gate electrode structure of the second PMOS device 3474. Inone embodiment, the VT of the third PMOS device 3473 is between the VTof the first PMOS device 3472 and the second PMOS device 3474. In anembodiment, the differentiated VT between the third PMOS device 3473 andthe first PMOS device 3472 is achieved by using modulated ordifferentiated implant doping at a region 3482 of the third PMOS device3473. In one such embodiment, the third P-type device 3473 has a channelregion having a dopant concentration different than a dopantconcentration of a channel region of the second P-type device 3474.

FIGS. 35A-35D illustrate cross-sectional views of various operations ina method of fabricating NMOS devices having a differentiated voltagethreshold based on differentiated gate electrode structure, inaccordance with another embodiment of the present disclosure.

Referring to FIG. 35A, where a “standard VT NMOS” region (STD VT NMOS)and a “high VT NMOS” region (HIGH VT NMOS) are shown as bifurcated on acommon substrate, a method of fabricating an integrated circuitstructure includes forming a gate dielectric layer 3506 over a firstsemiconductor fin 3502 and over a second semiconductor fin 3504, such asover first and second silicon fins. A P-type metal layer 3508 is formedon the gate dielectric layer 3506 over the first semiconductor fin 3502and over the second semiconductor fin 3504.

Referring to FIG. 35B, a portion of the P-type metal layer 3508 isremoved from the gate dielectric layer 3506 over the first semiconductorfin 3502, but a portion 3509 of the P-type metal layer 3508 is retainedon the gate dielectric layer 3506 over the second semiconductor fin3504.

Referring to FIG. 35C, an N-type metal layer 3510 is formed on the gatedielectric layer 3506 over the first semiconductor fin 3502, and on theportion 3509 of the P-type metal layer on the gate dielectric layer 3506over the second semiconductor fin 3504. In an embodiment, subsequentprocessing includes forming a first N-type device having a voltagethreshold (VT) over the first semiconductor fin 3502, and forming asecond N-type device having a voltage threshold (VT) over the secondsemiconductor fin 3504, wherein the VT of the second N-type device ishigher than the VT of the first N-type device.

Referring to FIG. 35D, in an embodiment, a conductive fill metal layer3512 is formed on the N-type metal layer 3510. In one such embodiment,forming the conductive fill metal layer 3512 includes forming atungsten-containing film using atomic layer deposition (ALD) with atungsten hexafluoride (WF₆) precursor.

FIGS. 36A-36D illustrate cross-sectional views of various operations ina method of fabricating PMOS devices having a differentiated voltagethreshold based on differentiated gate electrode structure, inaccordance with another embodiment of the present disclosure.

Referring to FIG. 36A, where a “standard VT PMOS” region (STD VT PMOS)and a “low VT PMOS” region (LOW VT PMOS) are shown as bifurcated on acommon substrate, a method of fabricating an integrated circuitstructure includes forming a gate dielectric layer 3606 over a firstsemiconductor fin 3602 and over a second semiconductor fin 3604, such asover first and second silicon fins. A first P-type metal layer 3608 isformed on the gate dielectric layer 3606 over the first semiconductorfin 3602 and over the second semiconductor fin 3604.

Referring to FIG. 36B, a portion of the first P-type metal layer 3608 isremoved from the gate dielectric layer 3606 over the first semiconductorfin 3602, but a portion 3609 of the first P-type metal layer 3608 isretained on the gate dielectric layer 3606 over the second semiconductorfin 3604.

Referring to FIG. 36C, a second P-type metal layer 3610 is formed on thegate dielectric layer 3606 over the first semiconductor fin 3602, and onthe portion 3609 of the first P-type metal layer on the gate dielectriclayer 3606 over the second semiconductor fin 3604. In an embodiment,subsequent processing includes forming a first P-type device having avoltage threshold (VT) over the first semiconductor fin 3602, andforming a second P-type device having a voltage threshold (VT) over thesecond semiconductor fin 3604, wherein the VT of the second P-typedevice is lower than the VT of the first P-type device.

In one embodiment, the first P-type metal layer 3608 and the secondP-type metal layer 3610 have a same composition. In one embodiment, thefirst P-type metal layer 3608 and the second P-type metal layer 3610have a same thickness. In one embodiment, the first P-type metal layer3608 and the second P-type metal layer 3610 have a same thickness and asame composition. In one embodiment, a seam 3611 is between the firstP-type metal layer 3608 and the second P-type metal layer 3610, as isdepicted.

Referring to FIG. 36D, in an embodiment, a conductive fill metal layer3612 is formed over the P-type metal layer 3610. In one such embodiment,forming the conductive fill metal layer 3612 includes forming atungsten-containing film using atomic layer deposition (ALD) with atungsten hexafluoride (WF₆) precursor. In one embodiment, an N-typemetal layer 3614 is formed on the P-type metal layer 3610 prior toforming the conductive fill metal layer 3612, as is depicted. In onesuch embodiment, the N-type metal layer 3614 is an artifact of a dualmetal gate replacement processing scheme.

In another aspect, metal gate structures for complementary metal oxidesemiconductor (CMOS) semiconductor devices are described. In an example,FIG. 37 illustrates a cross-sectional view of an integrated circuitstructure having a P/N junction, in accordance with an embodiment of thepresent disclosure.

Referring to FIG. 37, an integrated circuit structure 3700 includes asemiconductor substrate 3702 having an N well region 3704 having a firstsemiconductor fin 3706 protruding therefrom and a P well region 3708having a second semiconductor fin 3710 protruding therefrom. The firstsemiconductor fin 3706 is spaced apart from the second semiconductor fin3710. The N well region 3704 is directly adjacent to the P well region3708 in the semiconductor substrate 3702. A trench isolation structure3712 is on the semiconductor substrate 3702 outside of and between thefirst 3706 and second 3210 semiconductor fins. The first 3706 and second3210 semiconductor fins extend above the trench isolation structure3712.

A gate dielectric layer 3714 is on the first 3706 and second 3710semiconductor fins and on the trench isolation structure 3712. The gatedielectric layer 3714 is continuous between the first 3706 and second3710 semiconductor fins. A conductive layer 3716 is over the gatedielectric layer 3714 over the first semiconductor fin 3706 but not overthe second semiconductor fin 3710. In one embodiment, the conductivelayer 3716 includes titanium, nitrogen and oxygen. A p type metal gatelayer 3718 is over the conductive layer 3716 over the firstsemiconductor fin 3706 but not over the second semiconductor fin 3710.The p type metal gate layer 3718 is further on a portion of but not allof the trench isolation structure 3712 between the first semiconductorfin 3706 and the second semiconductor fin 3710. An n type metal gatelayer 3720 is over the second semiconductor fin 3710, over the trenchisolation structure 3712 between the first semiconductor fin 3706 andthe second semiconductor fin 3710, and over the p type metal gate layer3718.

In one embodiment, an inter-layer dielectric (ILD) layer 3722 is abovethe trench isolation structure 3712 on the outsides of the firstsemiconductor fin 3706 and the second semiconductor fin 3710. The ILDlayer 3722 has an opening 3724, the opening 3724 exposing the first 3706and second 3710 semiconductor fins. In one such embodiment, theconductive layer 3716, the p type metal gate layer 3718, and the n typemetal gate layer 3720 are further formed along a sidewall 3726 of theopening 3724, as is depicted. In a particular embodiment, the conductivelayer 3716 has a top surface 3717 along the sidewall 3726 of the opening3724 below a top surface 3719 of the p type metal gate layer 3718 and atop surface 3721 of the n type metal gate layer 3720 along the sidewall3726 of the opening 3724, as is depicted.

In one embodiment, the p type metal gate layer 3718 includes titaniumand nitrogen. In one embodiment, the n type metal gate layer 3720includes titanium and aluminum. In one embodiment, a conductive fillmetal layer 3730 is over the n type metal gate layer 3720, as isdepicted. In one such embodiment, the conductive fill metal layer 3730includes tungsten. In a particular embodiment, the conductive fill metallayer 3730 includes 95 or greater atomic percent tungsten and 0.1 to 2atomic percent fluorine. In one embodiment, the gate dielectric layer3714 has a layer including hafnium and oxygen. In one embodiment, athermal or chemical oxide layer 3732 is between upper portions of thefirst 3706 and second 3710 semiconductor fins, as is depicted. In oneembodiment, the semiconductor substrate 3702 is a bulk siliconsemiconductor substrate.

Referring now to only the right-hand side of FIG. 37, in accordance withan embodiment of the present disclosure, an integrated circuit structureincludes a semiconductor substrate 3702 including an N well region 3704having a semiconductor fin 3706 protruding therefrom. A trench isolationstructure 3712 is on the semiconductor substrate 3702 around thesemiconductor fin 3706. The semiconductor fin 3706 extends above thetrench isolation structure 3712. A gate dielectric layer 3714 is overthe semiconductor fin 3706. A conductive layer 3716 is over the gatedielectric layer 3714 over the semiconductor fin 3706. In oneembodiment, the conductive layer 3716 includes titanium, nitrogen andoxygen. A P-type metal gate layer 3718 is over the conductive layer 3716over the semiconductor fin 3706.

In one embodiment, an inter-layer dielectric (ILD) layer 3722 is abovethe trench isolation structure 3712. The ILD layer has an opening, theopening exposing the semiconductor fin 3706. The conductive layer 3716and the P-type metal gate layer 3718 are further formed along a sidewallof the opening. In one such embodiment, the conductive layer 3716 has atop surface along the sidewall of the opening below a top surface of theP-type metal gate layer 3718 along the sidewall of the opening. In oneembodiment, the P-type metal gate layer 3718 is on the conductive layer3716. In one embodiment, the P-type metal gate layer 3718 includestitanium and nitrogen. In one embodiment, a conductive fill metal layer3730 is over the P-type metal gate layer 3718. In one such embodiment,the conductive fill metal layer 3730 includes tungsten. In a particularsuch embodiment, the conductive fill metal layer 3730 is composed of 95or greater atomic percent tungsten and 0.1 to 2 atomic percent fluorine.In one embodiment, the gate dielectric layer 3714 includes a layerhaving hafnium and oxygen.

FIGS. 38A-38H illustrate cross-sectional views of various operations ina method of fabricating an integrated circuit structure using a dualmetal gate replacement gate process flow, in accordance with anembodiment of the present disclosure.

Referring to FIG. 38A, which shows an NMOS (N-type) regions and a PMOS(P-type) region, a method of fabricating an integrated circuit structureincludes forming an inter-layer dielectric (ILD) layer 3802 above first3804 and second 3806 semiconductor fins above a substrate 3800. Anopening 3808 is formed in the ILD layer 3802, the opening 3808 exposingthe first 3804 and second 3806 semiconductor fins. In one embodiment,the opening 3808 is formed by removing a gate placeholder or dummy gatestructure initially in place over the first 3804 and second 3806semiconductor fins.

A gate dielectric layer 3810 is formed in the opening 3808 and over thefirst 3804 and second 3806 semiconductor fins and on a portion of atrench isolation structure 3812 between the first 3804 and second 3806semiconductor fins. In one embodiments, the gate dielectric layer 3810is formed on a thermal or chemical oxide layer 3811, such as a siliconoxide or silicon dioxide layer, formed on the first 3804 and second 3806semiconductor fins, as is depicted. In another embodiment, the gatedielectric layer 3810 is formed directly on the first 3804 and second3806 semiconductor fins.

A conductive layer 3814 is formed over the gate dielectric layer 3810formed over the first 3804 and second 3806 semiconductor fins In oneembodiment, the conductive layer 3814 includes titanium, nitrogen andoxygen. A p type metal gate layer 3816 is formed over the conductivelayer 3814 formed over the first semiconductor fin 3804 and over thesecond 3806 semiconductor fin.

Referring to FIG. 38B, a dielectric etch stop layer 3818 is formed onthe p type metal gate layer 3816. In one embodiment, the dielectric etchstop layer 3818 includes a first layer of silicon oxide (e.g., SiO₂), alayer of aluminum oxide (e.g., Al₂O₃) on the first layer of siliconoxide, and a second layer of silicon oxide (e.g., SiO₂) on the layer ofaluminum oxide.

Referring to FIG. 38C, a mask 3820 is formed over the structure of FIG.38B. The mask 3820 covers the PMOS region and expose the NMOS region.

Referring to FIG. 38D, the dielectric etch stop layer 3818, the p typemetal gate layer 3816 and the conductive layer 3814 are patterned toprovide a patterned dielectric etch stop layer 3819, a patterned p typemetal gate layer 3817 over a patterned conductive layer 3815 over thefirst semiconductor fin 3804 but not over the second semiconductor fin3806. In an embodiment, the conductive layer 3814 protects the secondsemiconductor fin 3806 during the patterning.

Referring to FIG. 38E, the mask 3820 is removed from the structure ofFIG. 38D. Referring to FIG. 3F, the patterned dielectric etch stop layer3819 is removed from the structure of FIG. 3E.

Referring to FIG. 38G, an n type metal gate layer 3822 is formed overthe second semiconductor fin 3806, over the portion of the trenchisolation structure 3812 between the first 3804 and second 3806semiconductor fins, and over the patterned p type metal gate layer 3817.In an embodiment, the patterned conductive layer 3815, the patterned ptype metal gate layer 3817, and the n type metal gate layer 3822 arefurther formed along a sidewall 3824 of the opening 3808. In one suchembodiment, the patterned conductive layer 3815 has a top surface alongthe sidewall 3824 of the opening 3808 below a top surface of thepatterned p type metal gate layer 3817 and a top surface of the n typemetal gate layer 3822 along the sidewall 3824 of the opening 3808.

Referring to FIG. 38H, a conductive fill metal layer 3826 is formed overthe n type metal gate layer 3822. In one embodiment, the conductive fillmetal layer 3826 is formed by depositing a tungsten-containing filmusing atomic layer deposition (ALD) with a tungsten hexafluoride (WF₆)precursor.

In another aspect, dual silicide structures for complementary metaloxide semiconductor (CMOS) semiconductor devices are described. As anexemplary process flow, FIGS. 39A-39H illustrate cross-sectional viewsrepresenting various operations in a method of fabricating a dualsilicide based integrated circuit, in accordance with an embodiment ofthe present disclosure.

Referring to FIG. 39A, where an NMOS region and a PMOS regions are shownas bifurcated on a common substrate, a method of fabricating anintegrated circuit structure includes forming a first gate structure3902, which may include dielectric sidewall spacers 3903, over a firstfin 3904, such as a first silicon fin. A second gate structure 3952,which may include dielectric sidewall spacers 3953, is formed over asecond fin 3954, such as a second silicon fin. An insulating material3906 is formed adjacent to the first gate structure 3902 over the firstfin 3904 and adjacent to the second gate structure 3952 over the secondfin 3954. In one embodiment, the insulating material 3906 is asacrificial material and is used as a mask in a dual silicide process.

Referring to FIG. 39B, a first portion of the insulating material 3906is removed from over the first fin 3904 but not from over the second fin3954 to expose first 3908 and second 3910 source or drain regions of thefirst fin 3904 adjacent to the first gate structure 3902. In anembodiment, the first 3908 and second 3910 source or drain regions areepitaxial regions formed within recessed portions of the first fin 3904,as is depicted. In one such embodiment, the first 3908 and second 3910source or drain regions include silicon and germanium.

Referring to FIG. 39C, a first metal silicide layer 3912 is formed onthe first 3908 and second 3910 source or drain regions of the first fin3904. In one embodiment, the first metal silicide layer 3912 is formedby depositing a layer including nickel and platinum on the structure ofFIG. 39B, annealing the layer including nickel and platinum, andremoving unreacted portions of the layer including nickel and platinum.

Referring to FIG. 39D, subsequent to forming the first metal silicidelayer 3912, a second portion of the insulating material 3906 is removedfrom over the second fin 3954 to expose third 3958 and fourth 3960source or drain regions of the second fin 3954 adjacent to the secondgate structure 3952. In an embodiment, the second 3958 and third 3960source or drain regions are formed within the second fin 3954, such aswithin a second silicon fin, as is depicted. In another embodiment,however, the third 3958 and fourth 3960 source or drain regions areepitaxial regions formed within recessed portions of the second fin3954. In one such embodiment, the third 3958 and fourth 3960 source ordrain regions include silicon.

Referring to FIG. 39E, a first metal layer 3914 is formed on thestructure of FIG. 39D, i.e., on the first 3908, second 3910, third 3958and fourth 3960 source or drain regions. A second metal silicide layer3962 is then formed on the third 3958 and fourth 3960 source or drainregions of the second fin 3954. The second metal silicide layer 3962 isformed from the first metal layer 3914, e.g., using an anneal process.In an embodiment, the second metal silicide layer 3962 is different incomposition from the first metal silicide layer 3912. In one embodiment,the first metal layer 3914 is or includes a titanium layer. In oneembodiment, the first metal layer 3914 is formed as a conformal metallayer, e.g., conformal with the open trenches of FIG. 39D, as isdepicted.

Referring to FIG. 39F, in an embodiment, the first metal layer 3914 isrecessed to form a U-shaped metal layer 3916 above each of the first3908, second 3910, third 3958 and fourth 3960 source or drain regions.

Referring to FIG. 39G, in an embodiment, a second metal layer 3918 isformed on the U-shaped metal layer 3916 of the structure of FIG. 39F. Inan embodiment, the second metal layer 3918 is different in compositionthan the U-shaped metal layer 3916.

Referring to FIG. 39H, in an embodiment, a third metal layer 3920 isformed on the second metal layer 3918 of the structure of FIG. 39G. Inan embodiment, the third metal layer 3920 has a same composition as theU-shaped metal layer 3916.

Referring again to FIG. 3H, in accordance with an embodiment of thepresent disclosure, an integrated circuit structure 3900 includes aP-type semiconductor device (PMOS) above a substrate. The P-typesemiconductor device includes a first fin 3904, such as a first siliconfin. It is to be appreciated that the first fin has a top (shown as3904A) and sidewalls (e.g., into and out of the page). A first gateelectrode 3902 includes a first gate dielectric layer over the top 3904Aof the first fin 3904 and laterally adjacent the sidewalls of the firstfin 3904, and includes a first gate electrode over the first gatedielectric layer over the top 3904A of the first fin 3904 and laterallyadjacent the sidewalls of the first fin 3904. The first gate electrode3902 has a first side 3902A and a second side 3902B opposite the firstside 3902A.

First 3908 and second 3910 semiconductor source or drain regions areadjacent the first 3902A and second 3902B sides of the first gateelectrode 3902, respectively. First 3930 and second 3932 trench contactstructures are over the first 3908 and second 3910 semiconductor sourceor drain regions adjacent the first 3902A and second 3902B sides of thefirst gate electrode 3902, respectively. A first metal silicide layer3912 is directly between the first 3930 and second 3932 trench contactstructures and the first 3908 and second 3910 semiconductor source ordrain regions, respectively.

The integrated circuit structure 3900 includes an N-type semiconductordevice (NMOS) above the substrate. The N-type semiconductor deviceincludes a second fin 3954, such as a second silicon fin. It is to beappreciated that the second fin has a top (shown as 3954A) and sidewalls(e.g., into and out of the page). A second gate electrode 3952 includesa second gate dielectric layer over the top 3954A of the second fin 3954and laterally adjacent the sidewalls of the second fin 3954, andincludes a second gate electrode over the second gate dielectric layerover the top 3954A of the second fin 3954 and laterally adjacent thesidewalls of the second fin 3954. The second gate electrode 3952 has afirst side 3952A and a second side 3952B opposite the first side 3952A.

Third 3958 and fourth 3960 semiconductor source or drain regions areadjacent the first 3952A and second 3952B sides side of the second gateelectrode 3952, respectively. Third 3970 and fourth 3972 trench contactstructures are over the third 3958 and fourth 3960 semiconductor sourceor drain regions adjacent the first 3952A and second 3952B sides side ofthe second gate electrode 3952, respectively. A second metal silicidelayer 3962 is directly between the third 3970 and fourth 3972 trenchcontact structures and the third 3958 and fourth 3960 semiconductorsource or drain regions, respectively. In an embodiment, the first metalsilicide layer 3912 includes at least one metal species not included inthe second metal silicide layer 3962.

In one embodiment, the second metal silicide layer 3962 includestitanium and silicon. The first metal silicide layer 3912 includesnickel, platinum and silicon. In one embodiment, the first metalsilicide layer 3912 further includes germanium. In one embodiment, thefirst metal silicide layer 3912 further includes titanium, e.g., asincorporated into the first metal silicide layer 3912 during thesubsequent formation of the second metal silicide layer 3962 with firstmetal layer 3914. In one such embodiment, a silicide layer alreadyformed on a PMOS source or drain region is further modified by an annealprocess used to form a silicide region on an NMOS source or drainregion. This may result in a silicide layer on the PMOS source or drainregion that has fractional percentage of all siliciding metals. However,in other embodiments, such a silicide layer already formed on a PMOSsource or drain region does not change or does not change substantiallyby an anneal process used to form a silicide region on an NMOS source ordrain region.

In one embodiment, the first 3908 and second 3910 semiconductor sourceor drain regions are first and second embedded semiconductor source ordrain regions including silicon and germanium. In one such embodiment,the third 3958 and fourth 3960 semiconductor source or drain regions arethird and fourth embedded semiconductor source or drain regionsincluding silicon. In another embodiment, the third 3958 and fourth 3960semiconductor source or drain regions are formed in the fin 3954 and arenot embedded epitaxial regions.

In an embodiment, the first 3930, second 3932, third 3970 and fourth3972 trench contact structures all include a U-shaped metal layer 3916and a T-shaped metal layer 3918 on and over the entirety of the U-shapedmetal layer 3916. In one embodiment, the U-shaped metal layer 3916includes titanium, and the T-shaped metal layer 3918 includes cobalt. Inone embodiment, the first 3930, second 3932, third 3970 and fourth 3972trench contact structures all further include a third metal layer 3920on the T-shaped metal layer 3918. In one embodiment, the third metallayer 3920 and the U-shaped metal layer 3916 have a same composition. Ina particular embodiment, the third metal layer 3920 and the U-shapedmetal layer include titanium, and the T-shaped metal layer 3918 includescobalt.

In another aspect, trench contact structures, e.g., for source or drainregions, are described. In an example, FIG. 40A illustrates across-sectional view of an integrated circuit structure having trenchcontacts for an NMOS device, in accordance with an embodiment of thepresent disclosure. FIG. 40B illustrates a cross-sectional view of anintegrated circuit structure having trench contacts for a PMOS device,in accordance with another embodiment of the present disclosure.

Referring to FIG. 40A, an integrated circuit structure 4000 includes afin 4002, such as a silicon fin. A gate dielectric layer 4004 is overfin 4002. A gate electrode 4006 is over the gate dielectric layer 4004.In an embodiment, the gate electrode 4006 includes a conformalconductive layer 4008 and a conductive fill 4010. In an embodiment, adielectric cap 4012 is over the gate electrode 4006 and over the gatedielectric layer 4004. The gate electrode has a first side 4006A and asecond side 4006B opposite the first side 4006A. Dielectric spacers 4013are along the sidewalls of the gate electrode 4006. In one embodiment,the gate dielectric layer 4004 is further between a first of thedielectric spacers 4013 and the first side 4006A of the gate electrode4006, and between a second of the dielectric spacers 4013 and the secondside 4006B of the gate electrode 4006, as is depicted. In an embodiment,although not depicted, a thin oxide layer, such as a thermal or chemicalsilicon oxide or silicon dioxide layer, is between the fin 4002 and thegate dielectric layer 4004.

First 4014 and second 4016 semiconductor source or drain regions areadjacent the first 4006A and second 4006B sides of the gate electrode4006, respectively. In one embodiment, the first 4014 and second 4016semiconductor source or drain regions are in the fin 4002, as isdepicted. However, in another embodiment, the first 4014 and second 4016semiconductor source or drain regions are embedded epitaxial regionsformed in recesses of the fin 4002.

First 4018 and second 4020 trench contact structures are over the first4014 and second 4016 semiconductor source or drain regions adjacent thefirst 4006A and second 4006B sides of the gate electrode 4006,respectively. The first 4018 and second 4020 trench contact structuresboth include a U-shaped metal layer 4022 and a T-shaped metal layer 4024on and over the entirety of the U-shaped metal layer 4022. In oneembodiment, the U-shaped metal layer 4022 and the T-shaped metal layer4024 differ in composition. In one such embodiment, the U-shaped metallayer 4022 includes titanium, and the T-shaped metal layer 4024 includescobalt. In one embodiment, the first 4018 and second 4020 trench contactstructures both further include a third metal layer 4026 on the T-shapedmetal layer 4024. In one such embodiment, the third metal layer 4026 andthe U-shaped metal layer 4022 have a same composition. In a particularembodiment, the third metal layer 4026 and the U-shaped metal layer 4022include titanium, and the T-shaped metal layer 4024 includes cobalt.

A first trench contact via 4028 is electrically connected to the firsttrench contact 4018. In a particular embodiment, the first trenchcontact via 4028 is on and coupled to the third metal layer 4026 of thefirst trench contact 4018. The first trench contact via 4028 is furtherover and in contact with a portion of one of the dielectric spacers4013, and over and in contact with a portion of the dielectric cap 4012.A second trench contact via 4030 is electrically connected to the secondtrench contact 4020. In a particular embodiment, the second trenchcontact via 4030 is on and coupled to the third metal layer 4026 of thesecond trench contact 4020. The second trench contact via 4030 isfurther over and in contact with a portion of another of the dielectricspacers 4013, and over and in contact with another portion of thedielectric cap 4012.

In an embodiment, a metal silicide layer 4032 is directly between thefirst 4018 and second 4020 trench contact structures and the first 4014and second 4016 semiconductor source or drain regions, respectively. Inone embodiment, the metal silicide layer 4032 includes titanium andsilicon. In a particular such embodiment, the first 4014 and second 4016semiconductor source or drain regions are first and second N-typesemiconductor source or drain regions.

Referring to FIG. 40B, an integrated circuit structure 4050 includes afin 4052, such as a silicon fin. A gate dielectric layer 4054 is overfin 4052. A gate electrode 4056 is over the gate dielectric layer 4054.In an embodiment, the gate electrode 4056 includes a conformalconductive layer 4058 and a conductive fill 4060. In an embodiment, adielectric cap 4062 is over the gate electrode 4056 and over the gatedielectric layer 4054. The gate electrode has a first side 4056A and asecond side 4056B opposite the first side 4056A. Dielectric spacers 4063are along the sidewalls of the gate electrode 4056. In one embodiment,the gate dielectric layer 4054 is further between a first of thedielectric spacers 4063 and the first side 4056A of the gate electrode4056, and between a second of the dielectric spacers 4063 and the secondside 4056B of the gate electrode 4056, as is depicted. In an embodiment,although not depicted, a thin oxide layer, such as a thermal or chemicalsilicon oxide or silicon dioxide layer, is between the fin 4052 and thegate dielectric layer 4054.

First 4064 and second 4066 semiconductor source or drain regions areadjacent the first 4056A and second 4056B sides of the gate electrode4056, respectively. In one embodiment, the first 4064 and second 4066semiconductor source or drain regions are embedded epitaxial regionsformed in recesses 4065 and 4067, respectively, of the fin 4052, as isdepicted. However, in another embodiment, the first 4064 and second 4066semiconductor source or drain regions are in the fin 4052.

First 4068 and second 4070 trench contact structures are over the first4064 and second 4066 semiconductor source or drain regions adjacent thefirst 4056A and second 4056B sides of the gate electrode 4056,respectively. The first 4068 and second 4070 trench contact structuresboth include a U-shaped metal layer 4072 and a T-shaped metal layer 4074on and over the entirety of the U-shaped metal layer 4072. In oneembodiment, the U-shaped metal layer 4072 and the T-shaped metal layer4074 differ in composition. In one such embodiment, the U-shaped metallayer 4072 includes titanium, and the T-shaped metal layer 4074 includescobalt. In one embodiment, the first 4068 and second 4070 trench contactstructures both further include a third metal layer 4076 on the T-shapedmetal layer 4074. In one such embodiment, the third metal layer 4076 andthe U-shaped metal layer 4072 have a same composition. In a particularembodiment, the third metal layer 4076 and the U-shaped metal layer 4072include titanium, and the T-shaped metal layer 4074 includes cobalt.

A first trench contact via 4078 is electrically connected to the firsttrench contact 4068. In a particular embodiment, the first trenchcontact via 4078 is on and coupled to the third metal layer 4076 of thefirst trench contact 4068. The first trench contact via 4078 is furtherover and in contact with a portion of one of the dielectric spacers4063, and over and in contact with a portion of the dielectric cap 4062.A second trench contact via 4080 is electrically connected to the secondtrench contact 4070. In a particular embodiment, the second trenchcontact via 4080 is on and coupled to the third metal layer 4076 of thesecond trench contact 4070. The second trench contact via 4080 isfurther over and in contact with a portion of another of the dielectricspacers 4063, and over and in contact with another portion of thedielectric cap 4062.

In an embodiment, a metal silicide layer 4082 is directly between thefirst 4068 and second 4070 trench contact structures and the first 4064and second 4066 semiconductor source or drain regions, respectively. Inone embodiment, the metal silicide layer 4082 includes nickel, platinumand silicon. In a particular such embodiment, the first 4064 and second4066 semiconductor source or drain regions are first and second P-typesemiconductor source or drain regions. In one embodiment, the metalsilicide layer 4082 further includes germanium. In one embodiment, themetal silicide layer 4082 further includes titanium.

One or more embodiments described herein are directed to the use ofmetal chemical vapor deposition for wrap-around semiconductor contacts.Embodiments may be applicable to or include one or more of chemicalvapor deposition (CVD), plasma enhanced chemical vapor deposition(PECVD), atomic layer deposition (ALD), conductive contact fabrication,or thin films.

Particular embodiments may include the fabrication of a titanium or likemetallic layer using a low temperature (e.g., less than 500 degreesCelsius, or in the range of 400-500 degrees Celsius) chemical vapordeposition of a contact metal to provide a conformal source or draincontact. Implementation of such a conformal source or drain contact mayimprove three-dimensional (3D) transistor complementary metal oxidesemiconductor (CMOS) performance.

To provide context, metal to semiconductor contact layers may bedeposited using sputtering. Sputtering is a line of sight process andmay not be well suited to 3D transistor fabrication. Known sputteringsolutions have poor or incomplete metal-semiconductor junctions ondevice contact surfaces with an angle to the incidence of deposition.

In accordance with one or more embodiments of the present disclosure, alow temperature chemical vapor deposition process is implemented forfabrication of a contact metal to provide conformality in threedimensions and maximize the metal semiconductor junction contact area.The resulting greater contact area may reduce the resistance of thejunction. Embodiments may include deposition on semiconductor surfaceshaving a non-flat topography, where the topography of an area refers tothe surface shapes and features themselves, and a non-flat topographyincludes surface shapes and features or portions of surface shapes andfeatures that are non-flat, i.e., surface shapes and features that arenot entirely flat.

Embodiments described herein may include fabrication of wrap-aroundcontact structures. In one such embodiment, the use of pure metalconformally deposited onto transistor source-drain contacts by chemicalvapor deposition, plasma enhanced chemical vapor deposition, atomiclayer deposition, or plasma enhanced atomic layer deposition isdescribed. Such conformal deposition may be used to increase theavailable area of metal semiconductor contact and reduce resistance,improving the performance of the transistor device. In an embodiment,the relatively low temperature of the deposition leads to a minimizedresistance of the junction per unit area.

It is to be appreciated that a variety of integrated circuit structuresmay be fabricated using an integration scheme involving a metallic layerdeposition process as described herein. In accordance with an embodimentof the present disclosure, a method of fabricating an integrated circuitstructure includes providing a substrate in a chemical vapor deposition(CVD) chamber having an RF source, the substrate having a featurethereon. The method also includes reacting titanium tetrachloride(TiCl₄) and hydrogen (H₂) to form a titanium (Ti) layer on the featureof the substrate.

In an embodiment, the titanium layer has a total atomic compositionincluding 98% or greater of titanium and 0.5-2% of chlorine. Inalternative embodiments, a similar process is used to fabricate a highpurity metallic layer of zirconium (Zr), hafnium (Hf), tantalum (Ta),niobium (Nb), or vanadium (V). In an embodiment, there is relativelylittle film thickness variation, e.g., in an embodiment all coverage isgreater than 50% and nominal is 70% or greater (i.e., thicknessvariation of 30% or less). In an embodiment, thickness is measurablythicker on silicon (Si) or silicon germanium (SiGe) than other surfaces,as the Si or SiGe reacts during deposition and speeds uptake of the Ti.In an embodiment, the film composition includes approximately 0.5% Cl(or less than 1%) as an impurity, with essentially no other observedimpurities. In an embodiment, the deposition process enables metalcoverage on non-line of sight surfaces, such as surfaces hidden by asputter deposition line of sight. Embodiments described herein may beimplemented to improves transistor device drive by reducing the externalresistance of current being driven through the source and draincontacts.

In accordance with an embodiment of the present disclosure, the featureof the substrate is a source or drain contact trench exposing asemiconductor source or drain structure. The titanium layer (or otherhigh purity metallic layer) is a conductive contact layer for thesemiconductor source or drain structure. Exemplary embodiments of suchan implementation are described below in association with FIGS. 41A,41B, 42, 43A-43C and 44.

FIG. 41A illustrates a cross-sectional view of a semiconductor devicehaving a conductive contact on a source or drain region, in accordancewith an embodiment of the present disclosure.

Referring to FIG. 41A, a semiconductor structure 4100 includes a gatestructure 4102 above a substrate 4104. The gate structure 4102 includesa gate dielectric layer 4102A, a workfunction layer 4102B, and a gatefill 4102C. A source region 4108 and a drain region 4110 are on oppositesides of the gate structure 4102. Source or drain contacts 4112 areelectrically connected to the source region 4108 and the drain region4110, and are spaced apart of the gate structure 4102 by one or both ofan inter-layer dielectric layer 4114 or gate dielectric spacers 4116.The source region 4108 and the drain region 4110 are regions of thesubstrate 4104.

In an embodiment, the source or drain contacts 4112 include a highpurity metallic layer 4112A, such as described above, and a conductivetrench fill material 4112B. In one embodiment, the high purity metalliclayer 4112A has a total atomic composition including 98% or greater oftitanium. In one such embodiment, the total atomic composition of thehigh purity metallic layer 4112A further includes 0.5-2% of chlorine. Inan embodiment, the high purity metallic layer 4112A has a thicknessvariation of 30% or less. In an embodiment, the conductive trench fillmaterial 4112B is composed of a conductive material such as, but notlimited to, Cu, Al, W, or alloys thereof.

FIG. 41B illustrates a cross-sectional view of another semiconductordevice having a conductive on a raised source or drain region, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 41B, a semiconductor structure 4150 includes a gatestructure 4152 above a substrate 4154. The gate structure 4152 includesa gate dielectric layer 4152A, a workfunction layer 4152B, and a gatefill 4152C. A source region 4158 and a drain region 4160 are on oppositesides of the gate structure 4152. Source or drain contacts 4162 areelectrically connected to the source region 4158 and the drain region4160, and are spaced apart of the gate structure 4152 by one or both ofan inter-layer dielectric layer 4164 or gate dielectric spacers 4166.The source region 4158 and the drain region 4160 are epitaxial orembedded material regions formed in etched-out regions of the substrate4154. As is depicted, in an embodiment, the source region 4158 and thedrain region 4160 are raised source and drain regions. In a specificsuch embodiment, the raised source and drain regions are raised siliconsource and drain regions or raised silicon germanium source and drainregions.

In an embodiment, the source or drain contacts 4162 include a highpurity metallic layer 4162A, such as described above, and a conductivetrench fill material 4162B. In one embodiment, the high purity metalliclayer 4162A has a total atomic composition including 98% or greater oftitanium. In one such embodiment, the total atomic composition of thehigh purity metallic layer 4162A further includes 0.5-2% of chlorine. Inan embodiment, the high purity metallic layer 4162A has a thicknessvariation of 30% or less. In an embodiment, the conductive trench fillmaterial 4162B is composed of a conductive material such as, but notlimited to, Cu, Al, W, or alloys thereof.

Accordingly, in an embodiment, referring collectively to FIGS. 41A and41B, an integrated circuit structure includes a feature having a surface(source or drain contact trench exposing a semiconductor source or drainstructure). A high purity metallic layer 4112A or 4162A is on thesurface of the source or drain contact trench. It is to be appreciatedthat contact formation processes can involve consumption of an exposedsilicon or germanium or silicon germanium material of a source or drainregions. Such consumption can degrade device performance. In contrast,in accordance with an embodiment of the present disclosure, a surface(4149 or 4199) of the semiconductor source (4108 or 4158) or drain (4110or 4160) structure is not eroded or consumed, or is not substantiallyeroded or consumed beneath the source or drain contact trench. In onesuch embodiment, the lack of consumption or erosion arises from the lowtemperature deposition of the high purity metallic contact layer.

FIG. 42 illustrates a plan view of a plurality of gate lines over a pairof semiconductor fins, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 42, a plurality of active gate lines 4204 is formedover a plurality of semiconductor fins 4200. Dummy gate lines 4206 areat the ends of the plurality of semiconductor fins 4200. Spacings 4208between the gate lines 4204/4206 are locations where trench contacts maybe formed as conductive contacts to source or drain regions, such assource or drain regions 4251, 4252, 4253, and 4254.

FIGS. 43A-43C illustrate cross-sectional views, taken along the a-a′axis of FIG. 42, for various operations in a method of fabricating anintegrated circuit structure, in accordance with an embodiment of thepresent disclosure.

Referring to FIG. 43A, a plurality of active gate lines 4304 is formedover a semiconductor fin 4302 formed above a substrate 4300. Dummy gatelines 4306 are at the ends of the semiconductor fin 4302. A dielectriclayer 4310 is between the active gate lines 4304, between the dummy gatelines 4306 and the active gate lines 4304, and outside of the dummy gatelines 4306. Embedded source or drain structures 4308 are in thesemiconductor fin 4302 between the active gate lines 4304 and betweenthe dummy gate lines 4306 and the active gate lines 4304. The activegate lines 4304 include a gate dielectric layer 4312, a workfunctiongate electrode portion 4314 and a fill gate electrode portion 4316, anda dielectric capping layer 4318. Dielectric spacers 4320 line thesidewalls of the active gate lines 4304 and the dummy gate lines 4306.

Referring to FIG. 43B, the portion of the dielectric layer 4310 betweenthe active gate lines 4304 and between the dummy gate lines 4306 and theactive gate lines 4304 is removed to provide openings 4330 in locationswhere trench contacts are to be formed. Removal of the portion of thedielectric layer 4310 between the active gate lines 4304 and between thedummy gate lines 4306 and the active gate lines 4304 may lead to erosionof the embedded source or drain structures 4308 to provide erodedembedded source or drain structures 4332 which may have an uppersaddle-shaped topography, as is depicted in FIG. 43B.

Referring to FIG. 43C, trench contacts 4334 are formed in openings 4330between the active gate lines 4304 and between the dummy gate lines 4306and the active gate lines 4304. Each of the trench contacts 4334 mayinclude a metallic contact layer 4336 and a conductive fill material4338.

FIG. 44 illustrates a cross-sectional view, taken along the b-b′ axis ofFIG. 42, for an integrated circuit structure, in accordance with anembodiment of the present disclosure.

Referring to FIG. 44, fins 4402 are depicted above a substrate 4404.Lowe portions of the fins 4402 are surrounded by a trench isolationmaterial 4404. Upper portions of fins 4402 have been removed to enablegrowth of embedded source and drain structures 4406. A trench contact4408 is formed in an opening of a dielectric layer 4410, the openingexposing the embedded source and drain structures 4406. The trenchcontact includes a metallic contact layer 4412 and a conductive fillmaterial 4414. It is to be appreciated that, in accordance with anembodiment, the metallic contact layer 4412 extends to the top of thetrench contact 4408, as is depicted in FIG. 44. In another embodiment,however, the metallic contact layer 4412 does not extend to the top ofthe trench contact 4408 and is somewhat recessed within the trenchcontact 4408, e.g., similar to the depiction of metallic contact layer4336 in FIG. 43C.

Accordingly, referring collectively to FIGS. 42, 43A-43C and 44, inaccordance with an embodiment of the present disclosure, an integratedcircuit structure includes a semiconductor fin (4200, 4302, 4402) abovea substrate (4300, 4400). The semiconductor fin (4200, 4302, 4402)having a top and sidewalls. A gate electrode (4204, 4304) is over thetop and adjacent to the sidewalls of a portion of the semiconductor fin(4200, 4302, 4402). The gate electrode (4204, 4304) defines a channelregion in the semiconductor fin (4200, 4302, 4402). A firstsemiconductor source or drain structure (4251, 4332, 4406) is at a firstend of the channel region at a first side of the gate electrode (4204,4304), the first semiconductor source or drain structure (4251, 4332,4406) having a non-flat topography. A second semiconductor source ordrain structure (4252, 4332, 4406) is at a second end of the channelregion at a second side of the gate electrode (4204, 4304), the secondend opposite the first end, and the second side opposite the first side.The second semiconductor source or drain structure (4252, 4332, 4406)has a non-flat topography. A metallic contact material (4336, 4412) isdirectly on the first semiconductor source or drain structure (4251,4332, 4406) and directly on the second semiconductor source or drainstructure (4252, 4332, 4406). The metallic contact material (4336, 4412)is conformal with the non-flat topography of the first semiconductorsource or drain structure (4251, 4332, 4406) and conformal with thenon-flat topography of the second semiconductor source or drainstructure (4252, 4332, 4406).

In an embodiment, the metallic contact material (4336, 4412) has a totalatomic composition including 95% or greater of a single metal species.In one such embodiment, the metallic contact material (4336, 4412) has atotal atomic composition including 98% or greater of titanium. In aspecific such embodiment, the total atomic composition of metalliccontact material (4336, 4412) further includes 0.5-2% of chlorine. In anembodiment, the metallic contact material (4336, 4412) has a thicknessvariation of 30% or less along the non-flat topography of the firstsemiconductor source or drain structure (4251, 4332, 4406) and along thenon-flat topography of the second semiconductor source or drainstructure (4252, 4332, 4406).

In an embodiment, the non-flat topography of the first semiconductorsource or drain structure (4251, 4332, 4406) and the non-flat topographyof the second semiconductor source or drain structure (4252, 4332, 4406)both include a raised central portion and lower side portions, e.g., asis depicted in FIG. 44. In an embodiment, the non-flat topography of thefirst semiconductor source or drain structure (4251, 4332, 4406) and thenon-flat topography of the second semiconductor source or drainstructure (4252, 4332, 4406) both include saddle-shaped portions, e.g.,as is depicted in FIG. 43C.

In an embodiment, the first semiconductor source or drain structure(4251, 4332, 4406) and the second semiconductor source or drainstructure (4252, 4332, 4406) both include silicon. In an embodiment, thefirst semiconductor source or drain structure (4251, 4332, 4406) and thesecond semiconductor source or drain structure (4252, 4332, 4406) bothfurther include germanium, e.g., in the form of silicon germanium.

In an embodiment, the metallic contact material (4336, 4412) directly onthe first semiconductor source or drain structure (4251, 4332, 4406) isfurther along sidewalls of a trench in a dielectric layer (4320, 4410)over the first semiconductor source or drain structure (4251, 4332,4406), the trench exposing a portion of the first semiconductor sourceor drain structure (4251, 4332, 4406). In one such embodiment, athickness of the metallic contact material (4336) along the sidewalls ofthe trench thins from the first semiconductor source or drain structure(4336A at 4332) to a location (4336B) above the first semiconductorsource or drain structure (4332), an example of which is illustrated inFIG. 43C. In an embodiment, a conductive fill material (4338, 4414) ison the metallic contact material (4336, 4412) within the trench, as isdepicted in FIGS. 43C and 44.

In an embodiment, the integrated circuit structure further includes asecond semiconductor fin (e.g., upper fin 4200 of FIG. 42, 4302, 4402)having a top and sidewalls. The gate electrode (4204, 4304) is furtherover the top and adjacent to the sidewalls of a portion of the secondsemiconductor fin, the gate electrode defining a channel region in thesecond semiconductor fin. A third semiconductor source or drainstructure (4253, 4332, 4406) is at a first end of the channel region ofthe second semiconductor fin at the first side of the gate electrode(4204, 4304), the third semiconductor source or drain structure having anon-flat topography. A fourth semiconductor source or drain structure(4254, 4332, 4406) is at a second end of the channel region of thesecond semiconductor fin at the second side of the gate electrode (4204,4304), the second end opposite the first end, the fourth semiconductorsource or drain structure (4254, 4332, 4406) having a non-flattopography. The metallic contact material (4336, 4412) is directly onthe third semiconductor source or drain structure (4253, 4332, 4406) anddirectly on the fourth semiconductor source or drain structure (4254,4332, 4406), the metallic contact material (4336, 4412) conformal withthe non-flat topography of the third semiconductor source or drainstructure (4253, 4332, 4406) and conformal with the non-flat topographyof the fourth semiconductor source or drain structure (4254, 4332,4406). In an embodiment, the metallic contact material (4336, 4412) iscontinuous between the first semiconductor source or drain structure(4251, 4332, left side 4406) and the third semiconductor source or drainstructure (4253, 4332, right side 4406) and continuous between thesecond semiconductor source or drain structure (4252) and the fourthsemiconductor source or drain structure (4254).

In another aspect, a hardmask material be used to preserve (inhibiterosion), and may be retained over, a dielectric material in trench linelocations where conductive trench contacts are interrupted, e.g., incontact plug locations. For example, FIGS. 45A and 45B illustrate a planview and corresponding cross-sectional view, respectively, of anintegrated circuit structure including trench contact plugs with ahardmask material thereon, in accordance with an embodiment of thepresent disclosure.

Referring to FIGS. 45A and 45B, in an embodiment, an integrated circuitstructure 4500 includes a fin 4502A, such as a silicon fin. A pluralityof gate structures 4506 is over the fin 4502A. Individual ones of thegate structures 4506 are along a direction 4508 orthogonal to the fin4502A and has a pair of dielectric sidewall spacers 4510. A trenchcontact structure 4512 is over the fin 4502A and directly between thedielectric sidewalls spacers 4510 of a first pair 4506A/4506B of thegate structures 4506. A contact plug 4514B is over the fin 4502A anddirectly between the dielectric sidewalls spacers 4510 of a second pair4506B/4506C of the gate structures 4506. The contact plug 4514B includesa lower dielectric material 4516 and an upper hardmask material 4518.

In an embodiment, the lower dielectric material 4516 of the contact plug4516B includes silicon and oxygen, e.g., such as a silicon oxide orsilicon dioxide material. The upper hardmask material 4518 of thecontact plug 4516B includes silicon and nitrogen, e.g., such as asilicon nitride, silicon-rich nitride, or silicon-poor nitride material.

In an embodiment, the trench contact structure 4512 includes a lowerconductive structure 4520 and a dielectric cap 4522 on the lowerconductive structure 4520. In one embodiment, the dielectric cap 4522 ofthe trench contact structure 4512 has an upper surface co-planar with anupper surface of the upper hardmask material 4518 of the contact plug4514B, as is depicted.

In an embodiment, individual ones of the plurality of gate structures4506 include a gate electrode 4524 on a gate dielectric layer 4526. Adielectric cap 4528 is on the gate electrode 4524. In one embodiment,the dielectric cap 4528 of the individual ones of the plurality of gatestructures 4506 has an upper surface co-planar with an upper surface ofthe upper hardmask material 4518 of the contact plug 4514B, as isdepicted. In an embodiment, although not depicted, a thin oxide layer,such as a thermal or chemical silicon oxide or silicon dioxide layer, isbetween the fin 4502A and the gate dielectric layer 4526.

Referring again to FIGS. 45A and 45B, in an embodiment, an integratedcircuit structure 4500 includes a plurality of fins 4502, such as aplurality of silicon fins. Individual ones of the plurality of fins 4502are along a first direction 4504. A plurality of gate structures 4506 isover the plurality of fins 4502. Individual ones of the plurality ofgate structures 4506 are along a second direction 4508 orthogonal to thefirst direction 4504. Individual ones of the plurality of gatestructures 4506 have a pair of dielectric sidewall spacers 4510. Atrench contact structure 4512 is over a first fin 4502A of the pluralityof fins 4502 and directly between the dielectric sidewalls spacers 4510of a pair of the gate structures 4506. A contact plug 4514A is over asecond fin 4502B of the plurality of fins 4502 and directly between thedielectric sidewalls spacers 4510 of the pair of the gate structures4506. Similar to the cross-sectional view of a contact plug 4514B, thecontact plug 4514A includes a lower dielectric material 4516 and anupper hardmask material 4518.

In an embodiment, the lower dielectric material 4516 of the contact plug4516A includes silicon and oxygen, e.g., such as a silicon oxide orsilicon dioxide material. The upper hardmask material 4518 of thecontact plug 4516A includes silicon and nitrogen, e.g., such as asilicon nitride, silicon-rich nitride, or silicon-poor nitride material.

In an embodiment, the trench contact structure 4512 includes a lowerconductive structure 4520 and a dielectric cap 4522 on the lowerconductive structure 4520. In one embodiment, the dielectric cap 4522 ofthe trench contact structure 4512 has an upper surface co-planar with anupper surface of the upper hardmask material 4518 of the contact plug4514A or 4514B, as is depicted.

In an embodiment, individual ones of the plurality of gate structures4506 include a gate electrode 4524 on a gate dielectric layer 4526. Adielectric cap 4528 is on the gate electrode 4524. In one embodiment,the dielectric cap 4528 of the individual ones of the plurality of gatestructures 4506 has an upper surface co-planar with an upper surface ofthe upper hardmask material 4518 of the contact plug 4514A or 4514B, asis depicted. In an embodiment, although not depicted, a thin oxidelayer, such as a thermal or chemical silicon oxide or silicon dioxidelayer, is between the fin 4502A and the gate dielectric layer 4526.

One or more embodiments of the present disclosure are directed to a gatealigned contact process. Such a process may be implemented to formcontact structures for semiconductor structure fabrication, e.g., forintegrated circuit fabrication. In an embodiment, a contact pattern isformed as aligned to an existing gate pattern. By contrast, otherapproaches typically involve an additional lithography process withtight registration of a lithographic contact pattern to an existing gatepattern in combination with selective contact etches. For example,another process may include patterning of a poly (gate) grid withseparately patterning of contacts and contact plugs.

In accordance with one or more embodiments described herein, a method ofcontact formation involves formation of a contact pattern which isessentially perfectly aligned to an existing gate pattern whileeliminating the use of a lithographic operation with exceedingly tightregistration budget. In one such embodiment, this approach enables theuse of intrinsically highly selective wet etching (e.g., versus dry orplasma etching) to generate contact openings. In an embodiment, acontact pattern is formed by utilizing an existing gate pattern incombination with a contact plug lithography operation. In one suchembodiment, the approach enables elimination of the need for anotherwise critical lithography operation to generate a contact pattern,as used in other approaches. In an embodiment, a trench contact grid isnot separately patterned, but is rather formed between poly (gate)lines. For example, in one such embodiment, a trench contact grid isformed subsequent to gate grating patterning but prior to gate gratingcuts.

FIGS. 46A-46D illustrate cross-sectional views representing variousoperations in a method of fabricating an integrated circuit structureincluding trench contact plugs with a hardmask material thereon, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 46A, a method of fabricating an integrated circuitstructure includes forming a plurality of fins, individual ones 4602 ofthe plurality of fins along a first direction 4604. Individual ones 4602of the plurality of fins may include diffusion regions 4606. A pluralityof gate structures 4608 is formed over the plurality of fins. Individualones of the plurality of gate structures 4508 are along a seconddirection 4610 orthogonal to the first direction 4604 (e.g., direction4610 is into and out of the page). A sacrificial material structure 4612is formed between a first pair of the gate structures 4608. A contactplug 4614 between a second pair of the gate structures 4608. The contactplug includes a lower dielectric material 4616. A hardmask material 4618is on the lower dielectric material 4616.

In an embodiment, the gate structures 4608 include sacrificial or dummygate stacks and dielectric spacers 4609. The sacrificial or dummy gatestacks may be composed of polycrystalline silicon or silicon nitridepillars or some other sacrificial material, which may be referred to asgate dummy material.

Referring to FIG. 46B, the sacrificial material structure 4612 isremoved from the structure of FIG. 46A to form an opening 4620 betweenthe first pair of the gate structures 4608.

Referring to FIG. 46C, a trench contact structure 4622 is formed in theopening 4620 between the first pair of the gate structures 4608.Additionally, in an embodiment, as part of forming the trench contactstructure 4622, the hardmask 4618 of FIGS. 46A and 46B is planarized.Ultimately finalized contact plugs 4614′ include the lower dielectricmaterial 4616 and an upper hardmask material 4624 formed from thehardmask material 4618.

In an embodiment, the lower dielectric material 4616 of each of thecontact plugs 4614′ includes silicon and oxygen, and the upper hardmaskmaterial 4624 of each of the contact plugs 4614′ includes silicon andnitrogen. In an embodiment, each of the trench contact structures 4622includes a lower conductive structure 4626 and a dielectric cap 4628 onthe lower conductive structure 4626. In one embodiment, the dielectriccap 4628 of the trench contact structure 4622 has an upper surfaceco-planar with an upper surface of the upper hardmask material 4624 ofthe contact plug 4614′.

Referring to FIG. 46D, sacrificial or dummy gate stacks of gatestructures 4608 are replaced in a replacement gate process scheme. Insuch a scheme, dummy gate material, such as polysilicon or siliconnitride pillar material, is removed and replaced with permanent gateelectrode material. In one such embodiment, a permanent gate dielectriclayer is also formed in this process, as opposed to being carriedthrough from earlier processing.

Accordingly, permanent gate structures 4630 include a permanent gatedielectric layer 4632 and a permanent gate electrode layer or stack4634. Additionally, in an embodiment, a top portion of the permanentgate structures 4630 is removed, e.g., by an etch process, and replacedwith a dielectric cap 4636. In an embodiment, the dielectric cap 4636 ofthe individual ones of the permanent gate structures 4630 has an uppersurface co-planar with an upper surface of the upper hardmask material4624 of the contact plugs 4614′.

Referring again to FIGS. 46A-46D, in an embodiment, a replacement gateprocess is performed subsequent to forming trench contact structures4622, as is depicted. In accordance with other embodiments, however, areplacement gate process is performed prior to forming trench contactstructures 4622.

In another aspect, contact over active gate (COAG) structures andprocesses are described. One or more embodiments of the presentdisclosure are directed to semiconductor structures or devices havingone or more gate contact structures (e.g., as gate contact vias)disposed over active portions of gate electrodes of the semiconductorstructures or devices. One or more embodiments of the present disclosureare directed to methods of fabricating semiconductor structures ordevices having one or more gate contact structures formed over activeportions of gate electrodes of the semiconductor structures or devices.Approaches described herein may be used to reduce a standard cell areaby enabling gate contact formation over active gate regions. In one ormore embodiments, the gate contact structures fabricated to contact thegate electrodes are self-aligned via structures.

In technologies where space and layout constraints are somewhat relaxedcompared with current generation space and layout constraints, a contactto gate structure may be fabricated by making contact to a portion ofthe gate electrode disposed over an isolation region. As an example,FIG. 47A illustrates a plan view of a semiconductor device having a gatecontact disposed over an inactive portion of a gate electrode.

Referring to FIG. 47A, a semiconductor structure or device 4700Aincludes a diffusion or active region 4704 disposed in a substrate 4702,and within an isolation region 4706. One or more gate lines (also knownas poly lines), such as gate lines 4708A, 4708B and 4708C are disposedover the diffusion or active region 4704 as well as over a portion ofthe isolation region 4706. Source or drain contacts (also known astrench contacts), such as contacts 4710A and 4710B, are disposed oversource and drain regions of the semiconductor structure or device 4700A.Trench contact vias 4712A and 4712B provide contact to trench contacts4710A and 4710B, respectively. A separate gate contact 4714, andoverlying gate contact via 4716, provides contact to gate line 4708B. Incontrast to the source or drain trench contacts 4710A or 4710B, the gatecontact 4714 is disposed, from a plan view perspective, over isolationregion 4706, but not over diffusion or active region 4704. Furthermore,neither the gate contact 4714 nor gate contact via 4716 is disposedbetween the source or drain trench contacts 4710A and 4710B.

FIG. 47B illustrates a cross-sectional view of a non-planarsemiconductor device having a gate contact disposed over an inactiveportion of a gate electrode. Referring to FIG. 47B, a semiconductorstructure or device 4700B, e.g. a non-planar version of device 4700A ofFIG. 47A, includes a non-planar diffusion or active region 4704C (e.g.,a fin structure) formed from substrate 4702, and within isolation region4706. Gate line 4708B is disposed over the non-planar diffusion oractive region 4704B as well as over a portion of the isolation region4706. As shown, gate line 4708B includes a gate electrode 4750 and gatedielectric layer 4752, along with a dielectric cap layer 4754. Gatecontact 4714, and overlying gate contact via 4716 are also seen fromthis perspective, along with an overlying metal interconnect 4760, allof which are disposed in inter-layer dielectric stacks or layers 4770.Also seen from the perspective of FIG. 47B, the gate contact 4714 isdisposed over isolation region 4706, but not over non-planar diffusionor active region 4704B.

Referring again to FIGS. 47A and 47B, the arrangement of semiconductorstructure or device 4700A and 4700B, respectively, places the gatecontact over isolation regions. Such an arrangement wastes layout space.However, placing the gate contact over active regions would requireeither an extremely tight registration budget or gate dimensions wouldhave to increase to provide enough space to land the gate contact.Furthermore, historically, contact to gate over diffusion regions hasbeen avoided for risk of drilling through other gate material (e.g.,polysilicon) and contacting the underlying active region. One or moreembodiments described herein address the above issues by providingfeasible approaches, and the resulting structures, to fabricatingcontact structures that contact portions of a gate electrode formed overa diffusion or active region.

As an example, FIG. 48A illustrates a plan view of a semiconductordevice having a gate contact via disposed over an active portion of agate electrode, in accordance with an embodiment of the presentdisclosure. Referring to FIG. 48A, a semiconductor structure or device4800A includes a diffusion or active region 4804 disposed in a substrate4802, and within an isolation region 4806. One or more gate lines, suchas gate lines 4808A, 4808B and 4808C are disposed over the diffusion oractive region 4804 as well as over a portion of the isolation region4806. Source or drain trench contacts, such as trench contacts 4810A and4810B, are disposed over source and drain regions of the semiconductorstructure or device 4800A. Trench contact vias 4812A and 4812B providecontact to trench contacts 4810A and 4810B, respectively. A gate contactvia 4816, with no intervening separate gate contact layer, providescontact to gate line 4808B. In contrast to FIG. 47A, the gate contact4816 is disposed, from a plan view perspective, over the diffusion oractive region 4804 and between the source or drain contacts 4810A and4810B.

FIG. 48B illustrates a cross-sectional view of a non-planarsemiconductor device having a gate contact via disposed over an activeportion of a gate electrode, in accordance with an embodiment of thepresent disclosure. Referring to FIG. 48B, a semiconductor structure ordevice 4800B, e.g. a non-planar version of device 4800A of FIG. 48A,includes a non-planar diffusion or active region 4804B (e.g., a finstructure) formed from substrate 4802, and within isolation region 4806.Gate line 4808B is disposed over the non-planar diffusion or activeregion 4804B as well as over a portion of the isolation region 4806. Asshown, gate line 4808B includes a gate electrode 4850 and gatedielectric layer 4852, along with a dielectric cap layer 4854. The gatecontact via 4816 is also seen from this perspective, along with anoverlying metal interconnect 4860, both of which are disposed ininter-layer dielectric stacks or layers 4870. Also seen from theperspective of FIG. 48B, the gate contact via 4816 is disposed overnon-planar diffusion or active region 4804B.

Thus, referring again to FIGS. 48A and 48B, in an embodiment, trenchcontact vias 4812A, 4812B and gate contact via 4816 are formed in a samelayer and are essentially co-planar. In comparison to FIGS. 47A and 47B,the contact to the gate line would otherwise include and additional gatecontact layer, e.g., which could be run perpendicular to thecorresponding gate line. In the structure(s) described in associationwith FIGS. 48A and 48B, however, the fabrication of structures 4800A and4800B, respectively, enables the landing of a contact directly from ametal interconnect layer on an active gate portion without shorting toadjacent source drain regions. In an embodiment, such an arrangementprovides a large area reduction in circuit layout by eliminating theneed to extend transistor gates on isolation to form a reliable contact.As used throughout, in an embodiment, reference to an active portion ofa gate refers to that portion of a gate line or structure disposed over(from a plan view perspective) an active or diffusion region of anunderlying substrate. In an embodiment, reference to an inactive portionof a gate refers to that portion of a gate line or structure disposedover (from a plan view perspective) an isolation region of an underlyingsubstrate.

In an embodiment, the semiconductor structure or device 4800 is anon-planar device such as, but not limited to, a fin-FET or a tri-gatedevice. In such an embodiment, a corresponding semiconducting channelregion is composed of or is formed in a three-dimensional body. In onesuch embodiment, the gate electrode stacks of gate lines 4808A-4808Csurround at least a top surface and a pair of sidewalls of thethree-dimensional body. In another embodiment, at least the channelregion is made to be a discrete three-dimensional body, such as in agate-all-around device. In one such embodiment, the gate electrodestacks of gate lines 4808A-4808C each completely surrounds the channelregion.

More generally, one or more embodiments are directed to approaches for,and structures formed from, landing a gate contact via directly on anactive transistor gate. Such approaches may eliminate the need forextension of a gate line on isolation for contact purposes. Suchapproaches may also eliminate the need for a separate gate contact (GCN)layer to conduct signals from a gate line or structure. In anembodiment, eliminating the above features is achieved by recessingcontact metals in a trench contact (TCN) and introducing an additionaldielectric material in the process flow (e.g., TILA). The additionaldielectric material is included as a trench contact dielectric cap layerwith etch characteristics different from the gate dielectric materialcap layer already used for trench contact alignment in a gate alignedcontact process (GAP) processing scheme (e.g., GILA).

As an exemplary fabrication scheme, FIGS. 49A-49D illustratecross-sectional views representing various operations in a method offabricating a semiconductor structure having a gate contact structuredisposed over an active portion of a gate, in accordance with anembodiment of the present disclosure.

Referring to FIG. 49A, a semiconductor structure 4900 is providedfollowing trench contact (TCN) formation. It is to be appreciated thatthe specific arrangement of structure 4900 is used for illustrationpurposes only, and that a variety of possible layouts may benefit fromembodiments of the disclosure described herein. The semiconductorstructure 4900 includes one or more gate stack structures, such as gatestack structures 4908A-4908E disposed above a substrate 4902. The gatestack structures may include a gate dielectric layer and a gateelectrode. Trench contacts, e.g., contacts to diffusion regions ofsubstrate 4902, such as trench contacts 4910A-4910C are also included instructure 4900 and are spaced apart from gate stack structures4908A-4908E by dielectric spacers 4920. An insulating cap layer 4922 maybe disposed on the gate stack structures 4908A-4908E (e.g., GILA), as isalso depicted in FIG. 49A. As is also depicted in FIG. 49A, contactblocking regions or “contact plugs,” such as region 4923 fabricated froman inter-layer dielectric material, may be included in regions wherecontact formation is to be blocked.

In an embodiment, providing structure 4900 involves formation of acontact pattern which is essentially perfectly aligned to an existinggate pattern while eliminating the use of a lithographic operation withexceedingly tight registration budget. In one such embodiment, thisapproach enables the use of intrinsically highly selective wet etching(e.g., versus dry or plasma etching) to generate contact openings. In anembodiment, a contact pattern is formed by utilizing an existing gatepattern in combination with a contact plug lithography operation. In onesuch embodiment, the approach enables elimination of the need for anotherwise critical lithography operation to generate a contact pattern,as used in other approaches. In an embodiment, a trench contact grid isnot separately patterned, but is rather formed between poly (gate)lines. For example, in one such embodiment, a trench contact grid isformed subsequent to gate grating patterning but prior to gate gratingcuts.

Furthermore, the gate stack structures 4908A-4908E may be fabricated bya replacement gate process. In such a scheme, dummy gate material suchas polysilicon or silicon nitride pillar material, may be removed andreplaced with permanent gate electrode material. In one such embodiment,a permanent gate dielectric layer is also formed in this process, asopposed to being carried through from earlier processing. In anembodiment, dummy gates are removed by a dry etch or wet etch process.In one embodiment, dummy gates are composed of polycrystalline siliconor amorphous silicon and are removed with a dry etch process includingSF₆. In another embodiment, dummy gates are composed of polycrystallinesilicon or amorphous silicon and are removed with a wet etch processincluding aqueous NH₄OH or tetramethylammonium hydroxide. In oneembodiment, dummy gates are composed of silicon nitride and are removedwith a wet etch including aqueous phosphoric acid.

In an embodiment, one or more approaches described herein contemplateessentially a dummy and replacement gate process in combination with adummy and replacement contact process to arrive at structure 4900. Inone such embodiment, the replacement contact process is performed afterthe replacement gate process to allow high temperature anneal of atleast a portion of the permanent gate stack. For example, in a specificsuch embodiment, an anneal of at least a portion of the permanent gatestructures, e.g., after a gate dielectric layer is formed, is performedat a temperature greater than approximately 600 degrees Celsius. Theanneal is performed prior to formation of the permanent contacts.

Referring to FIG. 49B, the trench contacts 4910A-4910C of the structure4900 are recessed within spacers 4920 to provide recessed trenchcontacts 4911A-4911C that have a height below the top surface of spacers4920 and insulating cap layer 4922. An insulating cap layer 4924 is thenformed on recessed trench contacts 4911A-4911C (e.g., TILA). Inaccordance with an embodiment of the present disclosure, the insulatingcap layer 4924 on recessed trench contacts 4911A-4911C is composed of amaterial having a different etch characteristic than insulating caplayer 4922 on gate stack structures 4908A-4908E. As will be seen insubsequent processing operations, such a difference may be exploited toetch one of 4922/4924 selectively from the other of 4922/4924.

The trench contacts 4910A-4910C may be recessed by a process selectiveto the materials of spacers 4920 and insulating cap layer 4922. Forexample, in one embodiment, the trench contacts 4910A-4910C are recessedby an etch process such as a wet etch process or dry etch process.Insulating cap layer 4924 may be formed by a process suitable to providea conformal and sealing layer above the exposed portions of trenchcontacts 4910A-4910C. For example, in one embodiment, insulating caplayer 4924 is formed by a chemical vapor deposition (CVD) process as aconformal layer above the entire structure. The conformal layer is thenplanarized, e.g., by chemical mechanical polishing (CMP), to provideinsulating cap layer 4924 material only above trench contacts4910A-4910C, and re-exposing spacers 4920 and insulating cap layer 4922.

Regarding suitable material combinations for insulating cap layers4922/4924, in one embodiment, one of the pair of 4922/4924 is composedof silicon oxide while the other is composed of silicon nitride. Inanother embodiment, one of the pair of 4922/4924 is composed of siliconoxide while the other is composed of carbon doped silicon nitride. Inanother embodiment, one of the pair of 4922/4924 is composed of siliconoxide while the other is composed of silicon carbide. In anotherembodiment, one of the pair of 4922/4924 is composed of silicon nitridewhile the other is composed of carbon doped silicon nitride. In anotherembodiment, one of the pair of 4922/4924 is composed of silicon nitridewhile the other is composed of silicon carbide. In another embodiment,one of the pair of 4922/4924 is composed of carbon doped silicon nitridewhile the other is composed of silicon carbide.

Referring to FIG. 49C, an inter-layer dielectric (ILD) 4930 and hardmask4932 stack is formed and patterned to provide, e.g., a metal (O) trench4934 patterned above the structure of FIG. 49B.

The inter-layer dielectric (ILD) 4930 may be composed of a materialsuitable to electrically isolate metal features ultimately formedtherein while maintaining a robust structure between front end and backend processing. Furthermore, in an embodiment, the composition of theILD 4930 is selected to be consistent with via etch selectivity fortrench contact dielectric cap layer patterning, as described in greaterdetail below in association with FIG. 49D. In one embodiment, the ILD4930 is composed of a single or several layers of silicon oxide or asingle or several layers of a carbon doped oxide (CDO) material.However, in other embodiments, the ILD 4930 has a bi-layer compositionwith a top portion composed of a different material than an underlyingbottom portion of the ILD 4930. The hardmask layer 4932 may be composedof a material suitable to act as a subsequent sacrificial layer. Forexample, in one embodiment, the hardmask layer 4932 is composedsubstantially of carbon, e.g., as a layer of cross-linked organicpolymer. In other embodiments, a silicon nitride or carbon-doped siliconnitride layer is used as a hardmask 4932. The inter-layer dielectric(ILD) 4930 and hardmask 4932 stack may be patterned by a lithography andetch process.

Referring to FIG. 49D, via openings 4936 (e.g., VCT) are formed ininter-layer dielectric (ILD) 4930, extending from metal (O) trench 4934to one or more of the recessed trench contacts 4911A-4911C. For example,in FIG. 49D, via openings are formed to expose recessed trench contacts4911A and 4911C. The formation of via openings 4936 includes etching ofboth inter-layer dielectric (ILD) 4930 and respective portions ofcorresponding insulating cap layer 4924. In one such embodiment, aportion of insulating cap layer 4922 is exposed during patterning ofinter-layer dielectric (ILD) 4930 (e.g., a portion of insulating caplayer 4922 over gate stack structures 4908B and 4908E is exposed). Inthat embodiment, insulating cap layer 4924 is etched to form viaopenings 4936 selective to (i.e., without significantly etching orimpacting) insulating cap layer 4922.

In one embodiment, a via opening pattern is ultimately transferred tothe insulating cap layer 4924 (i.e., the trench contact insulating caplayers) by an etch process without etching the insulating cap layer 4922(i.e., the gate insulating cap layers). The insulating cap layer 4924(TILA) may be composed of any of the following or a combinationincluding silicon oxide, silicon nitride, silicon carbide, carbon dopedsilicon nitrides, carbon doped silicon oxides, amorphous silicon,various metal oxides and silicates including zirconium oxide, hafniumoxide, lanthanum oxide or a combination thereof. The layer may bedeposited using any of the following techniques including CVD, ALD,PECVD, PVD, HDP assisted CVD, low temperature CVD. A correspondingplasma dry etch is developed as a combination of chemical and physicalsputtering mechanisms. Coincident polymer deposition may be used tocontrol material removal rate, etch profiles and film selectivity. Thedry etch is typically generated with a mix of gases that include NF₃,CHF₃, C₄F₈, HBr and O₂ with typically pressures in the range of 30-100mTorr and a plasma bias of 50-1000 Watts. The dry etch may be engineeredto achieve significant etch selectivity between cap layer 4924 (TILA)and 4922 (GILA) layers to minimize the loss of 4922 (GILA) during dryetch of 4924 (TILA) to form contacts to the source drain regions of thetransistor.

Referring again to FIG. 49D, it is to be appreciated that a similarapproach may be implemented to fabricate a via opening pattern that isultimately transferred to the insulating cap layer 4922 (i.e., thetrench contact insulating cap layers) by an etch process without etchingthe insulating cap layer 4924 (i.e., the gate insulating cap layers).

To further exemplify concepts of a contact over active gate (COAG)technology, FIG. 50 illustrates a plan view and correspondingcross-sectional views of an integrated circuit structure having trenchcontacts including an overlying insulating cap layer, in accordance withan embodiment of the present disclosure.

Referring to FIG. 50, an integrated circuit structure 5000 includes agate line 5004 above a semiconductor substrate or fin 5002, such as asilicon fin. The gate line 5004 includes a gate stack 5005 (e.g.,including a gate dielectric layer or stack and a gate electrode on thegate dielectric layer or stack) and a gate insulating cap layer 5006 onthe gate stack 5005. Dielectric spacers 5008 are along sidewalls of thegate stack 5005 and, in an embodiment, along sidewalls of the gateinsulating cap layer 5006, as is depicted.

Trench contacts 5010 are adjacent the sidewalls of the gate line 5004,with the dielectric spacers 5008 between the gate line 5004 and thetrench contacts 5010. Individual ones of the trench contacts 5010include a conductive contact structure 5011 and a trench contactinsulating cap layer 5012 on the conductive contact structure 5011.

Referring again to FIG. 50, a gate contact via 5014 is formed in anopening of the gate insulating cap layer 5006 and electrically contactsthe gate stack 5005. In an embodiment, the gate contact via 5014electrically contacts the gate stack 5005 at a location over thesemiconductor substrate or fin 5002 and laterally between the trenchcontacts 5010, as is depicted. In one such embodiment, the trenchcontact insulating cap layer 5012 on the conductive contact structure5011 prevents gate to source shorting or gate to drain shorting by thegate contact via 5014.

Referring again to FIG. 50, trench contact vias 5016 are formed in anopening of the trench contact insulating cap layer 5012 and electricallycontact the respective conductive contact structures 5011. In anembodiment, the trench contact vias 5016 electrically contact therespective conductive contact structures 5011 at locations over thesemiconductor substrate or fin 5002 and laterally adjacent the gatestack 5005 of the gate line 5004, as is depicted. In one suchembodiment, the gate insulating cap layer 5006 on the gate stack 5005prevents source to gate shorting or drain to gate shorting by the trenchcontact vias 5016.

It is to be appreciated that differing structural relationships betweenan insulating gate cap layer and an insulating trench contact cap layermay be fabricated. As examples, FIGS. 51A-51F illustrate cross-sectionalviews of various integrated circuit structures, each having trenchcontacts including an overlying insulating cap layer and having gatestacks including an overlying insulating cap layer, in accordance withan embodiment of the present disclosure.

Referring to FIGS. 51A, 51B and 51C, integrated circuit structures5100A, 5100B and 5100C, respectively, includes a fin 5102, such as asilicon fin. Although depicted as a cross-sectional view, it is to beappreciated that the fin 5102 has a top 5102A and sidewalls (into andout of the page of the perspective shown). First 5104 and second 5106gate dielectric layers are over the top 5102A of the fin 5102 andlaterally adjacent the sidewalls of the fin 5102. First 5108 and second5110 gate electrodes are over the first 5104 and second 5106 gatedielectric layers, respectively, over the top 5102A of the fin 5102 andlaterally adjacent the sidewalls of the fin 5102. The first 5108 andsecond 5110 gate electrodes each include a conformal conductive layer5109A. such as a workfunction-setting layer, and a conductive fillmaterial 5109B above the conformal conductive layer 5109A. The first5108 and second 5110 gate electrodes both have a first side 5112 and asecond side 5114 opposite the first side 5112. The first 5108 and second5110 gate electrodes also both have an insulating cap 5116 having a topsurface 5118.

A first dielectric spacer 5120 is adjacent the first side 5112 of thefirst gate electrode 5108. A second dielectric spacer 5122 is adjacentthe second side 5114 of the second gate electrode 5110. A semiconductorsource or drain region 5124 is adjacent the first 5120 and second 5122dielectric spacers. A trench contact structure 5126 is over thesemiconductor source or drain region 5124 adjacent the first 5120 andsecond 5122 dielectric spacers.

The trench contact structure 5126 includes an insulating cap 5128 on aconductive structure 5130. The insulating cap 5128 of the trench contactstructure 5126 has a top surface 5129 substantially co-planar with a topsurfaces 5118 of the insulating caps 5116 of the first 5108 and second5110 gate electrodes. In an embodiment, the insulating cap 5128 of thetrench contact structure 5126 extends laterally into recesses 5132 inthe first 5120 and second 5122 dielectric spacers. In such anembodiment, the insulating cap 5128 of the trench contact structure 5126overhangs the conductive structure 5130 of the trench contact structure5126. In other embodiments, however, the insulating cap 5128 of thetrench contact structure 5126 does not extend laterally into recesses5132 in the first 5120 and second 5122 dielectric spacers and, hence,does not overhang the conductive structure 5130 of the trench contactstructure 5126.

It is to be appreciated that the conductive structure 5130 of the trenchcontact structure 5126 may not be rectangular, as depicted in FIGS.51A-51C. For example, the conductive structure 5130 of the trenchcontact structure 5126 may have a cross-sectional geometry similar to orthe same as the geometry shown for conductive structure 5130Aillustrated in the projection of FIG. 51A.

In an embodiment, the insulating cap 5128 of the trench contactstructure 5126 has a composition different than a composition of theinsulating caps 5116 of the first 5108 and second 5110 gate electrodes.In one such embodiment, the insulating cap 5128 of the trench contactstructure 5126 includes a carbide material, such as a silicon carbidematerial. The insulating caps 5116 of the first 5108 and second 5110gate electrodes include a nitride material, such as a silicon nitridematerial.

In an embodiment, the insulating caps 5116 of the first 5108 and second5110 gate electrodes both have a bottom surface 5117A below a bottomsurface 5128A of the insulating cap 5128 of the trench contact structure5126, as is depicted in FIG. 51A. In another embodiment, the insulatingcaps 5116 of the first 5108 and second 5110 gate electrodes both have abottom surface 5117B substantially co-planar with a bottom surface 5128Bof the insulating cap 5128 of the trench contact structure 5126, as isdepicted in FIG. 51B. In another embodiment, the insulating caps 5116 ofthe first 5108 and second 5110 gate electrodes both have a bottomsurface 5117C above a bottom surface 5128C of the insulating cap 5128 ofthe trench contact structure 5126, as is depicted in FIG. 51C.

In an embodiment, the conductive structure 5130 of the trench contactstructure 5128 includes a U-shaped metal layer 5134, a T-shaped metallayer 5136 on and over the entirety of the U-shaped metal layer 5134,and a third metal layer 5138 on the T-shaped metal layer 5136. Theinsulating cap 5128 of the trench contact structure 5126 is on the thirdmetal layer 5138. In one such embodiment, the third metal layer 5138 andthe U-shaped metal layer 5134 include titanium, and the T-shaped metallayer 5136 includes cobalt. In a particular such embodiment, theT-shaped metal layer 5136 further includes carbon.

In an embodiment, a metal silicide layer 5140 is directly between theconductive structure 5130 of the trench contact structure 5126 and thesemiconductor source or drain region 5124. In one such embodiment, themetal silicide layer 5140 includes titanium and silicon. In a particularsuch embodiment, the semiconductor source or drain region 5124 is anN-type semiconductor source or drain region. In another embodiment, themetal silicide layer 5140 includes nickel, platinum and silicon. In aparticular such embodiment, the semiconductor source or drain region5124 is a P-type semiconductor source or drain region. In anotherparticular such embodiment, the metal silicide layer further includesgermanium.

In an embodiment, referring to FIG. 51D, a conductive via 5150 is on andelectrically connected to a portion of the first gate electrode 5108over the top 5102A of the fin 5102. The conductive via 5150 is in anopening 5152 in the insulating cap 5116 of the first gate electrode5108. In one such embodiment, the conductive via 5150 is on a portion ofthe insulating cap 5128 of the trench contact structure 5126 but is notelectrically connected to the conductive structure 5130 of the trenchcontact structure 5126. In a particular such embodiment, the conductivevia 5150 is in an eroded portion 5154 of the insulating cap 5128 of thetrench contact structure 5126.

In an embodiment, referring to FIG. 51E, a conductive via 5160 is on andelectrically connected to a portion of the trench contact structure5126. The conductive via is in an opening 5162 of the insulating cap5128 of the trench contact structure 5126. In one such embodiment, theconductive via 5160 is on a portion of the insulating caps 5116 of thefirst 5108 and second 5110 gate electrodes but is not electricallyconnected to the first 5108 and second 5110 gate electrodes. In aparticular such embodiment, the conductive via 5160 is in an erodedportion 5164 of the insulating caps 5116 of the first 5108 and second5110 gate electrodes.

Referring again to FIG. 51E, in an embodiment, the conductive via 5160is a second conductive via in a same structure as the conductive via5150 of FIG. 51D. In one such embodiment, such a second conductive via5160 is isolated from the conductive via 5150. In another suchembodiment, such as second conductive via 5160 is merged with theconductive via 5150 to form an electrically shorting contact 5170, as isdepicted in FIG. 51F.

The approaches and structures described herein may enable formation ofother structures or devices that were not possible or difficult tofabricate using other methodologies. In a first example, FIG. 52Aillustrates a plan view of another semiconductor device having a gatecontact via disposed over an active portion of a gate, in accordancewith another embodiment of the present disclosure. Referring to FIG.52A, a semiconductor structure or device 5200 includes a plurality ofgate structures 5208A-5208C interdigitated with a plurality of trenchcontacts 5210A and 5210B (these features are disposed above an activeregion of a substrate, not shown). A gate contact via 5280 is formed onan active portion the gate structure 5208B. The gate contact via 5280 isfurther disposed on the active portion of the gate structure 5208C,coupling gate structures 5208B and 5208C. It is to be appreciated thatthe intervening trench contact 5210B may be isolated from the contact5280 by using a trench contact isolation cap layer (e.g., TILA). Thecontact configuration of FIG. 52A may provide an easier approach tostrapping adjacent gate lines in a layout, without the need to route thestrap through upper layers of metallization, hence enabling smaller cellareas or less intricate wiring schemes, or both.

In a second example, FIG. 52B illustrates a plan view of anothersemiconductor device having a trench contact via coupling a pair oftrench contacts, in accordance with another embodiment of the presentdisclosure. Referring to FIG. 52B, a semiconductor structure or device5250 includes a plurality of gate structures 5258A-5258C interdigitatedwith a plurality of trench contacts 5260A and 5260B (these features aredisposed above an active region of a substrate, not shown). A trenchcontact via 5290 is formed on the trench contact 5260A. The trenchcontact via 5290 is further disposed on the trench contact 5260B,coupling trench contacts 5260A and 5260B. It is to be appreciated thatthe intervening gate structure 5258B may be isolated from the trenchcontact via 5290 by using a gate isolation cap layer (e.g., by a GILAprocess). The contact configuration of FIG. 52B may provide an easierapproach to strapping adjacent trench contacts in a layout, without theneed to route the strap through upper layers of metallization, henceenabling smaller cell areas or less intricate wiring schemes, or both.

An insulating cap layer for a gate electrode may be fabricated usingseveral deposition operations and, as a result, may include artifacts ofa multi-deposition fabrication process. As an example, FIGS. 53A-53Eillustrate cross-sectional views representing various operations in amethod of fabricating an integrated circuit structure with a gate stackhaving an overlying insulating cap layer, in accordance with anembodiment of the present disclosure.

Referring to FIG. 53A, a starting structure 5300 includes a gate stack5304 above a substrate or fin 5302. The gate stack 5304 includes a gatedielectric layer 5306, a conformal conductive layer 5308, and aconductive fill material 5310. In an embodiment, the gate dielectriclayer 5306 is a high-k gate dielectric layer formed using an atomiclayer deposition (ALD) process, and the conformal conductive layer is aworkfunction layer formed using an ALD process. In one such embodiment,a thermal or chemical oxide layer 5312, such as a thermal or chemicalsilicon dioxide or silicon oxide layer, is between the substrate or fin5302 and the gate dielectric layer 5306. Dielectric spacers 5314, suchas silicon nitride spacers, are adjacent sidewalls of the gate stack5304. The dielectric gate stack 5304 and the dielectric spacers 5314 arehoused in an inter-layer-dielectric (ILD) layer 5316. In an embodiment,the gate stack 5304 is formed using a replacement gate and replacementgate dielectric processing scheme. A mask 5318 is patterned above thegate stack 5304 and ILD layer 5316 to provide an opening 5320 exposingthe gate stack 5304.

Referring to FIG. 53B, using a selective etch process or processes, thegate stack 5304, including gate dielectric layer 5306, conformalconductive layer 5308, and conductive fill material 5310, are recessedrelative to dielectric spacers 5314 and layer 5316. Mask 5318 is thenremoved. The recessing provides a cavity 5322 above a recessed gatestack 5324.

In another embodiment, not depicted, conformal conductive layer 5308 andconductive fill material 5310 are recessed relative to dielectricspacers 5314 and layer 5316, but gate dielectric layer 5306 is notrecessed or is only minimally recessed. It is to be appreciated that, inother embodiments, a maskless approach based on high etch selectivity isused for the recessing.

Referring to FIG. 53C, a first deposition process in a multi-depositionprocess for fabricating a gate insulating cap layer is performed. Thefirst deposition process is used to form a first insulating layer 5326conformal with the structure of FIG. 53B. In an embodiment, the firstinsulating layer 5326 includes silicon and nitrogen, e.g., the firstinsulating layer 5326 is a silicon nitride (Si₃N₄) layer, a silicon richsilicon nitride layer, a silicon-poor silicon nitride layer, or acarbon-doped silicon nitride layer. In an embodiment, the firstinsulating layer 5326 only partially fills the cavity 5322 above therecessed gate stack 5324, as is depicted.

Referring to FIG. 53D, the first insulating layer 5326 is subjected toan etch-back process, such as an anisotropic etch process, to providefirst portions 5328 of an insulating cap layer. The first portions 5328of an insulating cap layer only partially fill the cavity 5322 above therecessed gate stack 5324.

Referring to FIG. 53E, additional alternating deposition processes andetch-back processes are performed until cavity 5322 is filled with aninsulating gate cap structure 5330 above the recessed gate stack 5324.Seams 5332 may be evident in cross-sectional analysis and may beindicative of the number of alternating deposition processes andetch-back processes used to insulating gate cap structure 5330. In theexample shown in FIG. 53E, the presence of three sets of seams 5332A,5332B and 5332C is indicative of four alternating deposition processesand etch-back processes used to insulating gate cap structure 5330. Inan embodiment, the material 5330A, 5330B, 5330C and 5330D of insulatinggate cap structure 5330 separated by seams 5332 all have exactly orsubstantially the same composition.

As described throughout the present application, a substrate may becomposed of a semiconductor material that can withstand a manufacturingprocess and in which charge can migrate. In an embodiment, a substrateis described herein is a bulk substrate composed of a crystallinesilicon, silicon/germanium or germanium layer doped with a chargecarrier, such as but not limited to phosphorus, arsenic, boron or acombination thereof, to form an active region. In one embodiment, theconcentration of silicon atoms in such a bulk substrate is greater than97%. In another embodiment, a bulk substrate is composed of an epitaxiallayer grown atop a distinct crystalline substrate, e.g. a siliconepitaxial layer grown atop a boron-doped bulk silicon mono-crystallinesubstrate. A bulk substrate may alternatively be composed of a groupIII-V material. In an embodiment, a bulk substrate is composed of aIII-V material such as, but not limited to, gallium nitride, galliumphosphide, gallium arsenide, indium phosphide, indium antimonide, indiumgallium arsenide, aluminum gallium arsenide, indium gallium phosphide,or a combination thereof. In one embodiment, a bulk substrate iscomposed of a III-V material and the charge-carrier dopant impurityatoms are ones such as, but not limited to, carbon, silicon, germanium,oxygen, sulfur, selenium or tellurium.

As described throughout the present application, isolation regions suchas shallow trench isolation regions or sub-fin isolation regions may becomposed of a material suitable to ultimately electrically isolate, orcontribute to the isolation of, portions of a permanent gate structurefrom an underlying bulk substrate or to isolate active regions formedwithin an underlying bulk substrate, such as isolating fin activeregions. For example, in one embodiment, an isolation region is composedof one or more layers of a dielectric material such as, but not limitedto, silicon dioxide, silicon oxy-nitride, silicon nitride, carbon-dopedsilicon nitride, or a combination thereof.

As described throughout the present application, gate lines or gatestructures may be composed of a gate electrode stack which includes agate dielectric layer and a gate electrode layer. In an embodiment, thegate electrode of the gate electrode stack is composed of a metal gateand the gate dielectric layer is composed of a high-K material. Forexample, in one embodiment, the gate dielectric layer is composed of amaterial such as, but not limited to, hafnium oxide, hafniumoxy-nitride, hafnium silicate, lanthanum oxide, zirconium oxide,zirconium silicate, tantalum oxide, barium strontium titanate, bariumtitanate, strontium titanate, yttrium oxide, aluminum oxide, leadscandium tantalum oxide, lead zinc niobate, or a combination thereof.Furthermore, a portion of gate dielectric layer may include a layer ofnative oxide formed from the top few layers of a semiconductorsubstrate. In an embodiment, the gate dielectric layer is composed of atop high-k portion and a lower portion composed of an oxide of asemiconductor material. In one embodiment, the gate dielectric layer iscomposed of a top portion of hafnium oxide and a bottom portion ofsilicon dioxide or silicon oxy-nitride. In some implementations, aportion of the gate dielectric is a “U”-shaped structure that includes abottom portion substantially parallel to the surface of the substrateand two sidewall portions that are substantially perpendicular to thetop surface of the substrate.

In one embodiment, a gate electrode is composed of a metal layer suchas, but not limited to, metal nitrides, metal carbides, metal silicides,metal aluminides, hafnium, zirconium, titanium, tantalum, aluminum,ruthenium, palladium, platinum, cobalt, nickel or conductive metaloxides. In a specific embodiment, the gate electrode is composed of anon-workfunction-setting fill material formed above a metalworkfunction-setting layer. The gate electrode layer may consist of aP-type workfunction metal or an N-type workfunction metal, depending onwhether the transistor is to be a PMOS or an NMOS transistor. In someimplementations, the gate electrode layer may consist of a stack of twoor more metal layers, where one or more metal layers are workfunctionmetal layers and at least one metal layer is a conductive fill layer.For a PMOS transistor, metals that may be used for the gate electrodeinclude, but are not limited to, ruthenium, palladium, platinum, cobalt,nickel, and conductive metal oxides, e.g., ruthenium oxide. A P-typemetal layer will enable the formation of a PMOS gate electrode with aworkfunction that is between about 4.9 eV and about 5.2 eV. For an NMOStransistor, metals that may be used for the gate electrode include, butare not limited to, hafnium, zirconium, titanium, tantalum, aluminum,alloys of these metals, and carbides of these metals such as hafniumcarbide, zirconium carbide, titanium carbide, tantalum carbide, andaluminum carbide. An N-type metal layer will enable the formation of anNMOS gate electrode with a workfunction that is between about 3.9 eV andabout 4.2 eV. In some implementations, the gate electrode may consist ofa “U”-shaped structure that includes a bottom portion substantiallyparallel to the surface of the substrate and two sidewall portions thatare substantially perpendicular to the top surface of the substrate. Inanother implementation, at least one of the metal layers that form thegate electrode may simply be a planar layer that is substantiallyparallel to the top surface of the substrate and does not includesidewall portions substantially perpendicular to the top surface of thesubstrate. In further implementations of the disclosure, the gateelectrode may consist of a combination of U-shaped structures andplanar, non-U-shaped structures. For example, the gate electrode mayconsist of one or more U-shaped metal layers formed atop one or moreplanar, non-U-shaped layers.

As described throughout the present application, spacers associated withgate lines or electrode stacks may be composed of a material suitable toultimately electrically isolate, or contribute to the isolation of, apermanent gate structure from adjacent conductive contacts, such asself-aligned contacts. For example, in one embodiment, the spacers arecomposed of a dielectric material such as, but not limited to, silicondioxide, silicon oxy-nitride, silicon nitride, or carbon-doped siliconnitride.

In an embodiment, approaches described herein may involve formation of acontact pattern which is very well aligned to an existing gate patternwhile eliminating the use of a lithographic operation with exceedinglytight registration budget. In one such embodiment, this approach enablesthe use of intrinsically highly selective wet etching (e.g., versus dryor plasma etching) to generate contact openings. In an embodiment, acontact pattern is formed by utilizing an existing gate pattern incombination with a contact plug lithography operation. In one suchembodiment, the approach enables elimination of the need for anotherwise critical lithography operation to generate a contact pattern,as used in other approaches. In an embodiment, a trench contact grid isnot separately patterned, but is rather formed between poly (gate)lines. For example, in one such embodiment, a trench contact grid isformed subsequent to gate grating patterning but prior to gate gratingcuts.

Furthermore, a gate stack structure may be fabricated by a replacementgate process. In such a scheme, dummy gate material such as polysiliconor silicon nitride pillar material, may be removed and replaced withpermanent gate electrode material. In one such embodiment, a permanentgate dielectric layer is also formed in this process, as opposed tobeing carried through from earlier processing. In an embodiment, dummygates are removed by a dry etch or wet etch process. In one embodiment,dummy gates are composed of polycrystalline silicon or amorphous siliconand are removed with a dry etch process including use of SF₆. In anotherembodiment, dummy gates are composed of polycrystalline silicon oramorphous silicon and are removed with a wet etch process including useof aqueous NH₄OH or tetramethylammonium hydroxide. In one embodiment,dummy gates are composed of silicon nitride and are removed with a wetetch including aqueous phosphoric acid.

In an embodiment, one or more approaches described herein contemplateessentially a dummy and replacement gate process in combination with adummy and replacement contact process to arrive at structure. In onesuch embodiment, the replacement contact process is performed after thereplacement gate process to allow high temperature anneal of at least aportion of the permanent gate stack. For example, in a specific suchembodiment, an anneal of at least a portion of the permanent gatestructures, e.g., after a gate dielectric layer is formed, is performedat a temperature greater than approximately 600 degrees Celsius. Theanneal is performed prior to formation of the permanent contacts.

In some embodiments, the arrangement of a semiconductor structure ordevice places a gate contact over portions of a gate line or gate stackover isolation regions. However, such an arrangement may be viewed asinefficient use of layout space. In another embodiment, a semiconductordevice has contact structures that contact portions of a gate electrodeformed over an active region. In general, prior to (e.g., in additionto) forming a gate contact structure (such as a via) over an activeportion of a gate and in a same layer as a trench contact via, one ormore embodiments of the present disclosure include first using a gatealigned trench contact process. Such a process may be implemented toform trench contact structures for semiconductor structure fabrication,e.g., for integrated circuit fabrication. In an embodiment, a trenchcontact pattern is formed as aligned to an existing gate pattern. Bycontrast, other approaches typically involve an additional lithographyprocess with tight registration of a lithographic contact pattern to anexisting gate pattern in combination with selective contact etches. Forexample, another process may include patterning of a poly (gate) gridwith separate patterning of contact features.

It is to be appreciated that not all aspects of the processes describedabove need be practiced to fall within the spirit and scope ofembodiments of the present disclosure. For example, in one embodiment,dummy gates need not ever be formed prior to fabricating gate contactsover active portions of the gate stacks. The gate stacks described abovemay actually be permanent gate stacks as initially formed. Also, theprocesses described herein may be used to fabricate one or a pluralityof semiconductor devices. The semiconductor devices may be transistorsor like devices. For example, in an embodiment, the semiconductordevices are a metal-oxide semiconductor (MOS) transistors for logic ormemory, or are bipolar transistors. Also, in an embodiment, thesemiconductor devices have a three-dimensional architecture, such as atrigate device, an independently accessed double gate device, or aFIN-FET. One or more embodiments may be particularly useful forfabricating semiconductor devices at a 10 nanometer (10 nm) technologynode sub-10 nanometer (10 nm) technology node.

Additional or intermediate operations for FEOL layer or structurefabrication may include standard microelectronic fabrication processessuch as lithography, etch, thin films deposition, planarization (such aschemical mechanical polishing (CMP)), diffusion, metrology, the use ofsacrificial layers, the use of etch stop layers, the use ofplanarization stop layers, or any other associated action withmicroelectronic component fabrication. Also, it is to be appreciatedthat the process operations described for the preceding process flowsmay be practiced in alternative sequences, not every operation need beperformed or additional process operations may be performed, or both.

It is to be appreciated that in the above exemplary FEOL embodiments, inan embodiment, 10 nanometer or sub-10 nanometer node processing isimplemented directly in to the fabrication schemes and resultingstructures as a technology driver. In other embodiment, FEOLconsiderations may be driven by BEOL 10 nanometer or sub-10 nanometerprocessing requirements. For example, material selection and layouts forFEOL layers and devices may need to accommodate BEOL processing. In onesuch embodiment, material selection and gate stack architectures areselected to accommodate high density metallization of the BEOL layers,e.g., to reduce fringe capacitance in transistor structures formed inthe FEOL layers but coupled together by high density metallization ofthe BEOL layers.

Back end of line (BEOL) layers of integrated circuits commonly includeelectrically conductive microelectronic structures, which are known inthe arts as vias, to electrically connect metal lines or otherinterconnects above the vias to metal lines or other interconnects belowthe vias. Vias may be formed by a lithographic process.Representatively, a photoresist layer may be spin coated over adielectric layer, the photoresist layer may be exposed to patternedactinic radiation through a patterned mask, and then the exposed layermay be developed in order to form an opening in the photoresist layer.Next, an opening for the via may be etched in the dielectric layer byusing the opening in the photoresist layer as an etch mask. This openingis referred to as a via opening. Finally, the via opening may be filledwith one or more metals or other conductive materials to form the via.

Sizes and the spacing of vias has progressively decreased, and it isexpected that in the future the sizes and the spacing of the vias willcontinue to progressively decrease, for at least some types ofintegrated circuits (e.g., advanced microprocessors, chipset components,graphics chips, etc.). When patterning extremely small vias withextremely small pitches by such lithographic processes, severalchallenges present themselves. One such challenge is that the overlaybetween the vias and the overlying interconnects, and the overlaybetween the vias and the underlying landing interconnects, generallyneed to be controlled to high tolerances on the order of a quarter ofthe via pitch. As via pitches scale ever smaller over time, the overlaytolerances tend to scale with them at an even greater rate thanlithographic equipment is able to keep up.

Another such challenge is that the critical dimensions of the viaopenings generally tend to scale faster than the resolution capabilitiesof the lithographic scanners. Shrink technologies exist to shrink thecritical dimensions of the via openings. However, the shrink amounttends to be limited by the minimum via pitch, as well as by the abilityof the shrink process to be sufficiently optical proximity correction(OPC) neutral, and to not significantly compromise line width roughness(LWR) or critical dimension uniformity (CDU), or both. Yet another suchchallenge is that the LWR or CDU, or both, characteristics ofphotoresists generally need to improve as the critical dimensions of thevia openings decrease in order to maintain the same overall fraction ofthe critical dimension budget.

The above factors are also relevant for considering placement andscaling of non-conductive spaces or interruptions between metal lines(referred to as “plugs,” “dielectric plugs” or “metal line ends” amongthe metal lines of back end of line (BEOL) metal interconnectstructures. Thus, improvements are needed in the area of back endmetallization manufacturing technologies for fabricating metal lines,metal vias, and dielectric plugs.

In another aspect, a pitch quartering approach is implemented forpatterning trenches in a dielectric layer for forming BEOL interconnectstructures. In accordance with an embodiment of the present disclosure,pitch division is applied for fabricating metal lines in a BEOLfabrication scheme. Embodiments may enable continued scaling of thepitch of metal layers beyond the resolution capability of state-of-theart lithography equipment.

FIG. 54 is a schematic of a pitch quartering approach 5400 used tofabricate trenches for interconnect structures, in accordance with anembodiment of the present disclosure.

Referring to FIG. 54, at operation (a), backbone features 5402 areformed using direct lithography. For example, a photoresist layer orstack may be patterned and the pattern transferred into a hardmaskmaterial to ultimately form backbone features 5402. The photoresistlayer or stack used to form backbone features 5402 may be patternedusing standard lithographic processing techniques, such as 193 immersionlithography. First spacer features 5404 are then formed adjacent thesidewalls of the backbone features 5402.

At operation (b), the backbone features 5402 are removed to leave onlythe first spacer features 5404 remaining. At this stage, the firstspacer features 5404 are effectively a half pitch mask, e.g.,representing a pitch halving process. The first spacer features 5404 caneither be used directly for a pitch quartering process, or the patternof the first spacer features 5404 may first be transferred into a newhardmask material, where the latter approach is depicted.

At operation (c), the pattern of the first spacer features 5404transferred into a new hardmask material to form first spacer features5404′. Second spacer features 5406 are then formed adjacent thesidewalls of the first spacer features 5404′.

At operation (d), the first spacer features 5404′ are removed to leaveonly the second spacer features 5406 remaining. At this stage, thesecond spacer features 5406 are effectively a quarter pitch mask, e.g.,representing a pitch quartering process.

At operation (e), the second spacer features 5406 are used as a mask topattern a plurality of trenches 5408 in a dielectric or hardmask layer.The trenches may ultimately be filled with conductive material to formconductive interconnects in metallization layers of an integratedcircuit. Trenches 5408 having the label “B” correspond to backbonefeatures 5402. Trenches 5408 having the label “S” correspond to firstspacer features 5404 or 5404′. Trenches 5408 having the label “C”correspond to a complementary region 5407 between backbone features5402.

It is to be appreciated that since individual ones of the trenches 5408of FIG. 54 have a patterning origin that corresponds to one of backbonefeatures 5402, first spacer features 5404 or 5404′, or complementaryregion 5407 of FIG. 54, differences in width and/or pitch of suchfeatures may appear as artifacts of a pitch quartering process inultimately formed conductive interconnects in metallization layers of anintegrated circuit. As an example, FIG. 55A illustrates across-sectional view of a metallization layer fabricated using pitchquartering scheme, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 55A, an integrated circuit structure 5500 includes aninter-layer dielectric (ILD) layer 5504 above a substrate 5502. Aplurality of conductive interconnect lines 5506 is in the ILD layer5504, and individual ones of the plurality of conductive interconnectlines 5506 are spaced apart from one another by portions of the ILDlayer 5504. Individual ones of the plurality of conductive interconnectlines 5506 includes a conductive barrier layer 5508 and a conductivefill material 5510.

With reference to both FIGS. 54 and 55A, conductive interconnect lines5506B are formed in trenches with a pattern originating from backbonefeatures 5402. Conductive interconnect lines 5506S are formed intrenches with a pattern originating from first spacer features 5404 or5404′. Conductive interconnect lines 5506C are formed in trenches with apattern originating from complementary region 5407 between backbonefeatures 5402.

Referring again to FIG. 55A, in an embodiment, the plurality ofconductive interconnect lines 5506 includes a first interconnect line5506B having a width (W1). A second interconnect line 5506S isimmediately adjacent the first interconnect line 5506B, the secondinterconnect line 5506S having a width (W2) different than the width(W1) of the first interconnect line 5506B. A third interconnect line5506C is immediately adjacent the second interconnect line 5506S, thethird interconnect line 5506C having a width (W3). A fourth interconnectline (second 5506S) immediately adjacent the third interconnect line5506C, the fourth interconnect line having a width (W2) the same as thewidth (W2) of the second interconnect line 5506S. A fifth interconnectline (second 5506B) is immediately adjacent the fourth interconnect line(second 5506S), the fifth interconnect line (second 5506B) having awidth (W1) the same as the width (W1) of the first interconnect line5506B.

In an embodiment, the width (W3) of the third interconnect line 5506C isdifferent than the width (W1) of the first interconnect line 5506B. Inone such embodiment, the width (W3) of the third interconnect line 5506Cis different than the width (W2) of the second interconnect line 5506S.In another such embodiment, the width (W3) of the third interconnectline 5506C is the same as the width (W2) of the second interconnect line5506S. In another embodiment, the width (W3) of the third interconnectline 5506C is the same as the width (W1) of the first interconnect line5506B.

In an embodiment, a pitch (P1) between the first interconnect line 5506Band the third interconnect line 5506C is the same as a pitch (P2)between the second interconnect 5506S line and the fourth interconnectline (second 5506S). In another embodiment, a pitch (P1) between thefirst interconnect line 5506B and the third interconnect line 5506C isdifferent than a pitch (P2) between the second interconnect line 5506Sand the fourth interconnect line (second 5506S).

Referring again to FIG. 55A, in another embodiment, the plurality ofconductive interconnect lines 5506 includes a first interconnect line5506B having a width (W1). A second interconnect line 5506S isimmediately adjacent the first interconnect line 5506B, the secondinterconnect line 5506S having a width (W2). A third interconnect line5506C is immediately adjacent the second interconnect line 5506S, thethird interconnect line 5506S having a width (W3) different than thewidth (W1) of the first interconnect line 5506B. A fourth interconnectline (second 5506S) is immediately adjacent the third interconnect line5506C, the fourth interconnect line having a width (W2) the same as thewidth (W2) of the second interconnect line 5506S. A fifth interconnectline (second 5506B) is immediately adjacent the fourth interconnect line(second 5506S), the fifth interconnect line (second 5506B) having awidth (W1) the same as the width (W1) of the first interconnect line5506B.

In an embodiment, the width (W2) of the second interconnect line 5506Sis different than the width (W1) of the first interconnect line 5506B.In one such embodiment, the width (W3) of the third interconnect line5506C is different than the width (W2) of the second interconnect line5506S. In another such embodiment, the width (W3) of the thirdinterconnect line 5506C is the same as the width (W2) of the secondinterconnect line 5506S.

In an embodiment, the width (W2) of the second interconnect line 5506Sis the same as the width (W1) of the first interconnect line 5506B. Inan embodiment, a pitch (P1) between the first interconnect line 5506Band the third interconnect line 5506C is the same as a pitch (P2)between the second interconnect line 5506S and the fourth interconnectline (second 5506S). In an embodiment, a pitch (P1) between the firstinterconnect line 5506B and the third interconnect line 5506C isdifferent than a pitch (P2) between the second interconnect line 5506Sand the fourth interconnect line (second 5506S).

FIG. 55B illustrates a cross-sectional view of a metallization layerfabricated using pitch halving scheme above a metallization layerfabricated using pitch quartering scheme, in accordance with anembodiment of the present disclosure.

Referring to FIG. 55B, an integrated circuit structure 5550 includes afirst inter-layer dielectric (ILD) layer 5554 above a substrate 5552. Afirst plurality of conductive interconnect lines 5556 is in the firstILD layer 5554, and individual ones of the first plurality of conductiveinterconnect lines 5556 are spaced apart from one another by portions ofthe first ILD layer 5554. Individual ones of the plurality of conductiveinterconnect lines 5556 includes a conductive barrier layer 5558 and aconductive fill material 5560. The integrated circuit structure 5550further includes a second inter-layer dielectric (ILD) layer 5574 abovesubstrate 5552. A second plurality of conductive interconnect lines 5576is in the second ILD layer 5574, and individual ones of the secondplurality of conductive interconnect lines 5576 are spaced apart fromone another by portions of the second ILD layer 5574. Individual ones ofthe plurality of conductive interconnect lines 5576 includes aconductive barrier layer 5578 and a conductive fill material 5580.

In accordance with an embodiment of the present disclosure, withreference again to FIG. 55B, a method of fabricating an integratedcircuit structure includes forming a first plurality of conductiveinterconnect lines 5556 in and spaced apart by a first inter-layerdielectric (ILD) layer 5554 above a substrate 5552. The first pluralityof conductive interconnect lines 5556 is formed using a spacer-basedpitch quartering process, e.g., the approach described in associationwith operations (a)-(e) of FIG. 54. A second plurality of conductiveinterconnect lines 5576 is formed in and is spaced apart by a second ILDlayer 5574 above the first ILD layer 5554. The second plurality ofconductive interconnect lines 5576 is formed using a spacer-based pitchhalving process, e.g., the approach described in association withoperations (a) and (b) of FIG. 54.

In an embodiment, first plurality of conductive interconnect lines 5556has a pitch (P1) between immediately adjacent lines of than 40nanometers. The second plurality of conductive interconnect lines 5576has a pitch (P2) between immediately adjacent lines of 44 nanometers orgreater. In an embodiment, the spacer-based pitch quartering process andthe spacer-based pitch halving process are based on an immersion 193 nmlithography process.

In an embodiment, individual ones of the first plurality of conductiveinterconnect lines 5554 include a first conductive barrier liner 5558and a first conductive fill material 5560. Individual ones of the secondplurality of conductive interconnect lines 5556 include a secondconductive barrier liner 5578 and a second conductive fill material5580. In one such embodiment, the first conductive fill material 5560 isdifferent in composition from the second conductive fill material 5580.In another embodiment, the first conductive fill material 5560 is thesame in composition as the second conductive fill material 5580.

Although not depicted, in an embodiment, the method further includesforming a third plurality of conductive interconnect lines in and spacedapart by a third ILD layer above the second ILD layer 5574. The thirdplurality of conductive interconnect lines is formed without using pitchdivision.

Although not depicted, in an embodiment, the method further includes,prior to forming the second plurality of conductive interconnect lines5576, forming a third plurality of conductive interconnect lines in andspaced apart by a third ILD layer above the first ILD layer 5554. Thethird plurality of conductive interconnect lines is formed using aspacer-based pitch quartering process. In one such embodiment,subsequent to forming the second plurality of conductive interconnectlines 5576, a fourth plurality of conductive interconnect lines isformed in and is spaced apart by a fourth ILD layer above the second ILDlayer 5574. The fourth plurality of conductive interconnect lines isformed using a spacer-based pitch halving process. In an embodiment,such a method further includes forming a fifth plurality of conductiveinterconnect lines in and spaced apart by a fifth ILD layer above thefourth ILD layer, the fifth plurality of conductive interconnect linesformed using a spacer-based pitch halving process. A sixth plurality ofconductive interconnect lines is then formed in and spaced apart by asixth ILD layer above the fifth ILD layer, the sixth plurality ofconductive interconnect lines formed using a spacer-based pitch halvingprocess. A seventh plurality of conductive interconnect lines is thenformed in and spaced apart by a seventh ILD layer above the sixth ILDlayer. The seventh plurality of conductive interconnect lines is formedwithout using pitch division.

In another aspect, metal line compositions vary between metallizationlayers. Such an arrangement may be referred to as heterogeneousmetallization layers. In an embodiment, copper is used as a conductivefill material for relatively larger interconnect lines, while cobalt isused as a conductive fill material for relatively smaller interconnectlines. The smaller lines having cobalt as a fill material may providereduced electromigration while maintaining low resistivity. The use ofcobalt in place of copper for smaller interconnect lines may addressissues with scaling copper lines, where a conductive barrier layerconsumes a greater amount of an interconnect volume and copper isreduced, essentially hindering advantages normally associated with acopper interconnect line.

In a first example, FIG. 56A illustrates a cross-sectional view of anintegrated circuit structure having a metallization layer with a metalline composition above a metallization layer with a differing metal linecomposition, in accordance with an embodiment of the present disclosure.

Referring to FIG. 56A, an integrated circuit structure 5600 includes afirst plurality of conductive interconnect lines 5606 in and spacedapart by a first inter-layer dielectric (ILD) layer 5604 above asubstrate 5602. One of the conductive interconnect lines 5606A is shownas having an underlying via 5607. Individual ones of the first pluralityof conductive interconnect lines 5606 include a first conductive barriermaterial 5608 along sidewalls and a bottom of a first conductive fillmaterial 5610.

A second plurality of conductive interconnect lines 5616 is in andspaced apart by a second ILD layer 5614 above the first ILD layer 5604.One of the conductive interconnect lines 5616A is shown as having anunderlying via 5617. Individual ones of the second plurality ofconductive interconnect lines 5616 include a second conductive barriermaterial 5618 along sidewalls and a bottom of a second conductive fillmaterial 5620. The second conductive fill material 5620 is different incomposition from the first conductive fill material 5610.

In an embodiment, the second conductive fill material 5620 consistsessentially of copper, and the first conductive fill material 5610consists essentially of cobalt. In one such embodiment, the firstconductive barrier material 5608 is different in composition from thesecond conductive barrier material 5618. In another such embodiment, thefirst conductive barrier material 5608 is the same in composition as thesecond conductive barrier material 5618.

In an embodiment, the first conductive fill material 5610 includescopper having a first concentration of a dopant impurity atom, and thesecond conductive fill material 5620 includes copper having a secondconcentration of the dopant impurity atom. The second concentration ofthe dopant impurity atom is less than the first concentration of thedopant impurity atom. In one such embodiment, the dopant impurity atomis selected from the group consisting of aluminum (Al) and manganese(Mn). In an embodiment, the first conductive barrier material 5610 andthe second conductive barrier material 5620 have the same composition.In an embodiment, the first conductive barrier material 5610 and thesecond conductive barrier material 5620 have a different composition.

Referring again to FIG. 56A, the second ILD layer 5614 is on anetch-stop layer 5622. The conductive via 5617 is in the second ILD layer5614 and in an opening of the etch-stop layer 5622. In an embodiment,the first and second ILD layers 5604 and 5614 include silicon, carbonand oxygen, and the etch-stop layer 5622 includes silicon and nitrogen.In an embodiment, individual ones of the first plurality of conductiveinterconnect lines 5606 have a first width (W1), and individual ones ofthe second plurality of conductive interconnect lines 5616 have a secondwidth (W2) greater than the first width (W1).

In a second example, FIG. 56B illustrates a cross-sectional view of anintegrated circuit structure having a metallization layer with a metalline composition coupled to a metallization layer with a differing metalline composition, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 56B, an integrated circuit structure 5650 includes afirst plurality of conductive interconnect lines 5656 in and spacedapart by a first inter-layer dielectric (ILD) layer 5654 above asubstrate 5652. One of the conductive interconnect lines 5656A is shownas having an underlying via 5657. Individual ones of the first pluralityof conductive interconnect lines 5656 include a first conductive barriermaterial 5658 along sidewalls and a bottom of a first conductive fillmaterial 5660.

A second plurality of conductive interconnect lines 5666 is in andspaced apart by a second ILD layer 5664 above the first ILD layer 5654.One of the conductive interconnect lines 5666A is shown as having anunderlying via 5667. Individual ones of the second plurality ofconductive interconnect lines 5666 include a second conductive barriermaterial 5668 along sidewalls and a bottom of a second conductive fillmaterial 5670. The second conductive fill material 5670 is different incomposition from the first conductive fill material 5660.

In an embodiment, the conductive via 5657 is on and electrically coupledto an individual one 5656B of the first plurality of conductiveinterconnect lines 5656, electrically coupling the individual one 5666Aof the second plurality of conductive interconnect lines 5666 to theindividual one 5656B of the first plurality of conductive interconnectlines 5656. In an embodiment, individual ones of the first plurality ofconductive interconnect lines 5656 are along a first direction 5698(e.g., into and out of the page), and individual ones of the secondplurality of conductive interconnect lines 5666 are along a seconddirection 5699 orthogonal to the first direction 5698, as is depicted.In an embodiment, the conductive via 5667 includes the second conductivebarrier material 5668 along sidewalls and a bottom of the secondconductive fill material 5670, as is depicted.

In an embodiment, the second ILD layer 5664 is on an etch-stop layer5672 on the first ILD layer 5654. The conductive via 5667 is in thesecond ILD layer 5664 and in an opening of the etch-stop layer 5672. Inan embodiment, the first and second ILD layers 5654 and 5664 includesilicon, carbon and oxygen, and the etch-stop layer 5672 includessilicon and nitrogen. In an embodiment, individual ones of the firstplurality of conductive interconnect lines 5656 have a first width (W1),and individual ones of the second plurality of conductive interconnectlines 5666 have a second width (W2) greater than the first width (W1).

In an embodiment, the second conductive fill material 5670 consistsessentially of copper, and the first conductive fill material 5660consists essentially of cobalt. In one such embodiment, the firstconductive barrier material 5658 is different in composition from thesecond conductive barrier material 5668. In another such embodiment, thefirst conductive barrier material 5658 is the same in composition as thesecond conductive barrier material 5668.

In an embodiment, the first conductive fill material 5660 includescopper having a first concentration of a dopant impurity atom, and thesecond conductive fill material 5670 includes copper having a secondconcentration of the dopant impurity atom. The second concentration ofthe dopant impurity atom is less than the first concentration of thedopant impurity atom. In one such embodiment, the dopant impurity atomis selected from the group consisting of aluminum (Al) and manganese(Mn). In an embodiment, the first conductive barrier material 5660 andthe second conductive barrier material 5670 have the same composition.In an embodiment, the first conductive barrier material 5660 and thesecond conductive barrier material 5670 have a different composition.

FIGS. 57A-57C illustrate cross-section views of individual interconnectlines having various barrier liner and conductive capping structuralarrangements suitable for the structures described in association withFIGS. 56A and 56B, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 57A, an interconnect line 5700 in a dielectric layer5701 includes a conductive barrier material 5702 and a conductive fillmaterial 5704. The conductive barrier material 5702 includes an outerlayer 5706 distal from the conductive fill material 5704 and an innerlayer 5708 proximate to the conductive fill material 5704. In anembodiment, the conductive fill material includes cobalt, the outerlayer 5706 includes titanium and nitrogen, and the inner layer 5708includes tungsten, nitrogen and carbon. In one such embodiment, theouter layer 5706 has a thickness of approximately 2 nanometers, and theinner layer 5708 has a thickness of approximately 0.5 nanometers. Inanother embodiment, the conductive fill material includes cobalt, theouter layer 5706 includes tantalum, and the inner layer 5708 includesruthenium. In one such embodiment, the outer layer 5706 further includesnitrogen.

Referring to FIG. 57B, an interconnect line 5720 in a dielectric layer5721 includes a conductive barrier material 5722 and a conductive fillmaterial 5724. A conductive cap layer 5730 is on a top of the conductivefill material 5724. In one such embodiment, the conductive cap layer5730 is further on a top of the conductive barrier material 5722, as isdepicted. In another embodiment, the conductive cap layer 5730 is not ona top of the conductive barrier material 5722. In an embodiment, theconductive cap layer 5730 consists essentially of cobalt, and theconductive fill material 5724 consists essentially of copper.

Referring to FIG. 57C, an interconnect line 5740 in a dielectric layer5741 includes a conductive barrier material 5742 and a conductive fillmaterial 5744. The conductive barrier material 5742 includes an outerlayer 5746 distal from the conductive fill material 5744 and an innerlayer 5748 proximate to the conductive fill material 5744. A conductivecap layer 5750 is on a top of the conductive fill material 5744. In oneembodiment, the conductive cap layer 5750 is only a top of theconductive fill material 5744. In another embodiment, however, theconductive cap layer 5750 is further on a top of the inner layer 5748 ofthe conductive barrier material 5742, i.e., at location 5752. In onesuch embodiment, the conductive cap layer 5750 is further on a top ofthe outer layer 5746 of the conductive barrier material 5742, i.e., atlocation 5754.

In an embodiment, with reference to FIGS. 57B and 57C, a method offabricating an integrated circuit structure includes forming aninter-layer dielectric (ILD) layer 5721 or 5741 above a substrate. Aplurality of conductive interconnect lines 5720 or 5740 is formed intrenches in and spaced apart by the ILD layer, individual ones of theplurality of conductive interconnect lines 5720 or 5740 in acorresponding one of the trenches. The plurality of conductiveinterconnect lines is formed by first forming a conductive barriermaterial 5722 or 5724 on bottoms and sidewalls of the trenches, and thenforming a conductive fill material 5724 or 5744 on the conductivebarrier material 5722 or 5742, respectively, and filling the trenches,where the conductive barrier material 5722 or 5742 is along a bottom ofand along sidewalls of the conductive fill material 5730 or 5750,respectively. The top of the conductive fill material 5724 or 5744 isthen treated with a gas including oxygen and carbon. Subsequent totreating the top of the conductive fill material 5724 or 5744 with thegas including oxygen and carbon, a conductive cap layer 5730 or 5750 isformed on the top of the conductive fill material 5724 or 5744,respectively.

In one embodiment, treating the top of the conductive fill material 5724or 5744 with the gas including oxygen and carbon includes treating thetop of the conductive fill material 5724 or 5744 with carbon monoxide(CO). In one embodiment, the conductive fill material 5724 or 5744includes copper, and forming the conductive cap layer 5730 or 5750 onthe top of the conductive fill material 5724 or 5744 includes forming alayer including cobalt using chemical vapor deposition (CVD). In oneembodiment, the conductive cap layer 5730 or 5750 is formed on the topof the conductive fill material 5724 or 5744, but not on a top of theconductive barrier material 5722 or 5724.

In one embodiment, forming the conductive barrier material 5722 or 5744includes forming a first conductive layer on the bottoms and sidewallsof the trenches, the first conductive layer including tantalum. A firstportion of the first conductive layer is first formed using atomic layerdeposition (ALD) and then a second portion of the first conductive layeris then formed using physical vapor deposition (PVD). In one suchembodiment, forming the conductive barrier material further includesforming a second conductive layer on the first conductive layer on thebottoms and sidewalls of the trenches, the second conductive layerincluding ruthenium, and the conductive fill material including copper.In one embodiment, the first conductive layer further includes nitrogen.

FIG. 58 illustrates a cross-sectional view of an integrated circuitstructure having four metallization layers with a metal line compositionand pitch above two metallization layers with a differing metal linecomposition and smaller pitch, in accordance with an embodiment of thepresent disclosure.

Referring to FIG. 58, an integrated circuit structure 5800 includes afirst plurality of conductive interconnect lines 5804 in and spacedapart by a first inter-layer dielectric (ILD) layer 5802 above asubstrate 5801. Individual ones of the first plurality of conductiveinterconnect lines 5804 include a first conductive barrier material 5806along sidewalls and a bottom of a first conductive fill material 5808.Individual ones of the first plurality of conductive interconnect lines5804 are along a first direction 5898 (e.g., into and out of the page).

A second plurality of conductive interconnect lines 5814 is in andspaced apart by a second ILD layer 5812 above the first ILD layer 5802.Individual ones of the second plurality of conductive interconnect lines5814 include the first conductive barrier material 5806 along sidewallsand a bottom of the first conductive fill material 5808. Individual onesof the second plurality of conductive interconnect lines 5814 are alonga second direction 5899 orthogonal to the first direction 5898.

A third plurality of conductive interconnect lines 5824 is in and spacedapart by a third ILD layer 5822 above the second ILD layer 5812.Individual ones of the third plurality of conductive interconnect lines5824 include a second conductive barrier material 5826 along sidewallsand a bottom of a second conductive fill material 5828. The secondconductive fill material 5828 is different in composition from the firstconductive fill material 5808. Individual ones of the third plurality ofconductive interconnect lines 5824 are along the first direction. 5898.

A fourth plurality of conductive interconnect lines 5834 is in andspaced apart by a fourth ILD layer 5832 above the third ILD layer 5822.Individual ones of the fourth plurality of conductive interconnect lines5834 include the second conductive barrier material 5826 along sidewallsand a bottom of the second conductive fill material 5828. Individualones of the fourth plurality of conductive interconnect lines 5834 arealong the second direction 5899.

A fifth plurality of conductive interconnect lines 5844 is in and spacedapart by a fifth ILD layer 5842 above the fourth ILD layer 5832.Individual ones of the fifth plurality of conductive interconnect lines5844 include the second conductive barrier material 5826 along sidewallsand a bottom of the second conductive fill material 5828. Individualones of the fifth plurality of conductive interconnect lines 5844 arealong the first direction 5898.

A sixth plurality of conductive interconnect lines 5854 is in and spacedapart by a sixth ILD layer 5852 above the fifth ILD layer. Individualones of the sixth plurality of conductive interconnect lines 5854include the second conductive barrier material 5826 along sidewalls anda bottom of the second conductive fill material 5828. Individual ones ofthe sixth plurality of conductive interconnect lines 5854 are along thesecond direction 5899.

In an embodiment, the second conductive fill material 5828 consistsessentially of copper, and the first conductive fill material 5808consists essentially of cobalt. In an embodiment, the first conductivefill material 5808 includes copper having a first concentration of adopant impurity atom, and the second conductive fill material 5828includes copper having a second concentration of the dopant impurityatom, the second concentration of the dopant impurity atom less than thefirst concentration of the dopant impurity atom.

In an embodiment, the first conductive barrier material 5806 isdifferent in composition from the second conductive barrier material5826. In another embodiment, the first conductive barrier material 5806and the second conductive barrier material 5826 have the samecomposition.

In an embodiment, a first conductive via 5819 is on and electricallycoupled to an individual one 5804A of the first plurality of conductiveinterconnect lines 5804. An individual one 5814A of the second pluralityof conductive interconnect lines 5814 is on and electrically coupled tothe first conductive via 5819.

A second conductive via 5829 is on and electrically coupled to anindividual one 5814B of the second plurality of conductive interconnectlines 5814. An individual one 5824A of the third plurality of conductiveinterconnect lines 5824 is on and electrically coupled to the secondconductive via 5829.

A third conductive via 5839 is on and electrically coupled to anindividual one 5824B of the third plurality of conductive interconnectlines 5824. An individual one 5834A of the fourth plurality ofconductive interconnect lines 5834 is on and electrically coupled to thethird conductive via 5839.

A fourth conductive via 5849 is on and electrically coupled to anindividual one 5834B of the fourth plurality of conductive interconnectlines 5834. An individual one 5844A of the fifth plurality of conductiveinterconnect lines 5844 is on and electrically coupled to the fourthconductive via 5849.

A fifth conductive via 5859 is on and electrically coupled to anindividual one 5844B of the fifth plurality of conductive interconnectlines 5844. An individual one 5854A of the sixth plurality of conductiveinterconnect lines 5854 is on and electrically coupled to the fifthconductive via 5859.

In one embodiment, the first conductive via 5819 includes the firstconductive barrier material 5806 along sidewalls and a bottom of thefirst conductive fill material 5808. The second 5829, third 5839, fourth5849 and fifth 5859 conductive vias include the second conductivebarrier material 5826 along sidewalls and a bottom of the secondconductive fill material 5828.

In an embodiment, the first 5802, second 5812, third 5822, fourth 5832,fifth 5842 and sixth 5852 ILD layers are separated from one another by acorresponding etch-stop layer 5890 between adjacent ILD layers. In anembodiment, the first 5802, second 5812, third 5822, fourth 5832, fifth5842 and sixth 5852 ILD layers include silicon, carbon and oxygen.

In an embodiment, individual ones of the first 5804 and second 5814pluralities of conductive interconnect lines have a first width (W1).Individual ones of the third 5824, fourth 5834, fifth 5844 and sixth5854 pluralities of conductive interconnect lines have a second width(W2) greater than the first width (W1).

FIGS. 59A-59D illustrate cross-section views of various interconnectline ad via arrangements having a bottom conductive layer, in accordancewith an embodiment of the present disclosure.

Referring to FIGS. 59A and 59B, an integrated circuit structure 5900includes an inter-layer dielectric (ILD) layer 5904 above a substrate5902. A conductive via 5906 is in a first trench 5908 in the ILD layer5904. A conductive interconnect line 5910 is above and electricallycoupled to the conductive via 5906. The conductive interconnect line5910 is in a second trench 5912 in the ILD layer 5904. The second trench5912 has an opening 5913 larger than an opening 5909 of the first trench5908.

In an embodiment, the conductive via 5906 and the conductiveinterconnect line 5910 include a first conductive barrier layer 5914 ona bottom of the first trench 5908, but not along sidewalls of the firsttrench 5908, and not along a bottom and sidewalls of the second trench5912. A second conductive barrier layer 5916 is on the first conductivebarrier layer 5914 on the bottom of the first trench 5908. The secondconductive barrier layer 5916 is further along the sidewalls of thefirst trench 5908, and further along the bottom and sidewalls of thesecond trench 5912. A third conductive barrier layer 5918 is on thesecond conductive barrier layer 5916 on the bottom of the first trench5908. The third conductive barrier layer 5918 is further on the secondconductive barrier layer 5916 along the sidewalls of the first trench5908 and along the bottom and sidewalls of the second trench 5912. Aconductive fill material 5920 is on the third conductive barrier layer5918 and filling the first 5908 and second trenches 5912. The thirdconductive barrier layer 5918 is along a bottom of and along sidewallsof the conductive fill material 5920.

In one embodiment, the first conductive barrier layer 5914 and the thirdconductive barrier layer 5918 have the same composition, and the secondconductive barrier layer 5916 is different in composition from the firstconductive barrier layer 5914 and the third conductive barrier layer5918. In one such embodiment, the first conductive barrier layer 5914and the third conductive barrier layer 5918 include ruthenium, and thesecond conductive barrier layer 5916 includes tantalum. In a particularsuch embodiment, the second conductive barrier layer 5916 furtherincludes nitrogen. In an embodiment, the conductive fill material 5920consists essentially of copper.

In an embodiment, a conductive cap layer 5922 is on a top of theconductive fill material 5920. In one such embodiment, the conductivecap layer 5922 is not on a top of the second conductive barrier layer5916 and is not on a top of the third conductive barrier layer 5918.However, in another embodiment, the conductive cap layer 5922 is furtheron a top of the third conductive barrier layer 5918, e.g., at locations5924. In one such embodiment, the conductive cap layer 5922 is stillfurther on a top of the second conductive barrier layer 5916, e.g., atlocations 5926. In an embodiment, the conductive cap layer 5922 consistsessentially of cobalt, and the conductive fill material 5920 consistsessentially of copper.

Referring to FIGS. 59C and 59D, in an embodiment, the conductive via5906 is on and electrically connected to a second conductiveinterconnect line 5950 in a second ILD layer 5952 below the ILD layer5904. The second conductive interconnect line 5950 includes a conductivefill material 5954 and a conductive cap 5956 thereon. An etch stop layer5958 may be over the conductive cap 5956, as is depicted.

In one embodiment, the first conductive barrier layer 5914 of theconductive via 5906 is in an opening 5960 of the conductive cap 5956 ofthe second conductive interconnect line 5950, as is depicted in FIG.59C. In one such embodiment, the first conductive barrier layer 5914 ofthe conductive via 5906 includes ruthenium, and the conductive cap 5956of the second conductive interconnect line 5950 includes cobalt.

In another embodiment, the first conductive barrier layer 5914 of theconductive via 5906 is on a portion of the conductive cap 5956 of thesecond conductive interconnect line 5950, as is depicted in FIG. 59D. Inone such embodiment, the first conductive barrier layer 5914 of theconductive via 5906 includes ruthenium, and the conductive cap 5956 ofthe second conductive interconnect line 5950 includes cobalt. In aparticular embodiment, although not depicted, the first conductivebarrier layer 5914 of the conductive via 5906 is on a recess into butnot through the conductive cap 5956 of the second conductiveinterconnect line 5950.

In another aspect, a BEOL metallization layer has a non-planartopography, such as step-height differences between conducive lines andan ILD layer housing the conductive lines. In an embodiment, anoverlying etch-stop layer is formed conformal with the topography andtakes on the topography. In an embodiment, the topography aids inguiding an overlying via etching process toward the conductive lines tohinder “non-landedness” of conductive vias.

In a first example of etch stop layer topography, FIGS. 60A-60Dillustrate cross-sectional views of structural arrangements for arecessed line topography of a BEOL metallization layer, in accordancewith an embodiment of the present disclosure.

Referring to FIG. 60A, an integrated circuit structure 6000 includes aplurality of conductive interconnect lines 6006 in and spaced apart byan inter-layer dielectric (ILD) layer 6004 above a substrate 6002. Oneof the plurality of conductive interconnect lines 6006 is shown ascoupled to an underlying via 6007 for exemplary purposes. Individualones of the plurality of conductive interconnect lines 6006 have anupper surface 6008 below an upper surface 6010 of the ILD layer 6004. Anetch-stop layer 6012 is on and conformal with the ILD layer 6004 and theplurality of conductive interconnect lines 6006. The etch-stop layer6012 has a non-planar upper surface with an uppermost portion 6014 ofthe non-planar upper surface over the ILD layer 6004 and a lowermostportion 6016 of the non-planar upper surface over the plurality ofconductive interconnect lines 6006.

A conductive via 6018 is on and electrically coupled to an individualone 6006A of the plurality of conductive interconnect lines 6006. Theconductive via 6018 is in an opening 6020 of the etch-stop layer 6012.The opening 6020 is over the individual one 6006A of the plurality ofconductive interconnect lines 6006 but not over the ILD layer 6014. Theconductive via 6018 is in a second ILD layer 6022 above the etch-stoplayer 6012. In one embodiment, the second ILD layer 6022 is on andconformal with the etch-stop layer 6012, as is depicted in FIG. 60A.

In an embodiment, a center 6024 of the conductive via 6018 is alignedwith a center 6026 of the individual one 6006A of the plurality ofconductive interconnect lines 6006, as is depicted in FIG. 60A. Inanother embodiment, however, a center 6024 of the conductive via 6018 isoff-set from a center 6026 of the individual one 6006A of the pluralityof conductive interconnect lines 6006, as is depicted in FIG. 60B.

In an embodiment, individual ones of the plurality of conductiveinterconnect lines 6006 include a barrier layer 6028 along sidewalls anda bottom of a conductive fill material 6030. In one embodiment, both thebarrier layer 6028 and the conductive fill material 6030 have anuppermost surface below the upper surface 6010 of the ILD layer 6004, asis depicted in FIGS. 60A, 60B and 60C. In a particular such embodiment,the uppermost surface of the barrier layer 6028 is above the uppermostsurface of the conductive fill material 6030, as is depicted in FIG. 6C.In another embodiment, he conductive fill material 6030 has an uppermostsurface below the upper surface 6010 of the ILD layer 6004, and thebarrier layer 6028 has an uppermost surface co-planar with the uppersurface 6010 of the ILD layer 6004, as is depicted in FIG. 6D.

In an embodiment, the ILD layer 6004 includes silicon, carbon andoxygen, and the etch-stop layer 6012 includes silicon and nitrogen. Inan embodiment, the upper surface 6008 of the individual ones of theplurality of conductive interconnect lines 6006 is below the uppersurface 6010 of the ILD layer 6004 by an amount in the range of 0.5-1.5nanometers.

Referring collectively to FIGS. 60A-60D, in accordance with anembodiment of the present disclosure, a method of fabricating anintegrated circuit structure includes forming a plurality of conductiveinterconnect lines in and spaced apart by a first inter-layer dielectric(ILD) layer 6004 above a substrate 6002. The plurality of conductiveinterconnect lines is recessed relative to the first ILD layer toprovide individual ones 6006 of the plurality of conductive interconnectlines having an upper surface 6008 below an upper surface 6010 of thefirst ILD layer 6004. Subsequent to recessing the plurality ofconductive interconnect lines, an etch-stop layer 6012 is formed on andconformal with the first ILD layer 6004 and the plurality of conductiveinterconnect lines 6006. The etch-stop layer 6012 has a non-planar uppersurface with an uppermost portion 6016 of the non-planar upper surfaceover the first ILD layer 6004 and a lowermost portion 6014 of thenon-planar upper surface over the plurality of conductive interconnectlines 6006. A second ILD layer 6022 is formed on the etch-stop layer6012. A via trench is etched in the second ILD layer 6022. The etch-stoplayer 6012 directs the location of the via trench in the second ILDlayer 6022 during the etching. The etch-stop layer 6012 is etchedthrough the via trench to form an opening 6020 in the etch-stop layer6012. The opening 6020 is over an individual one 6006A of the pluralityof conductive interconnect lines 6006 but not over the first ILD layer6004. A conductive via 6018 is formed in the via trench and in theopening 6020 in the etch-stop layer 6012. The conductive via 6018 is onand electrically coupled to the individual one 6006A of the plurality ofconductive interconnect lines 6006.

In one embodiment, individual ones of the plurality of conductiveinterconnect lines 6006 include a barrier layer 6028 along sidewalls anda bottom of a conductive fill material 6030, and recessing the pluralityof conductive interconnect lines includes recessing both the barrierlayer 6028 and the conductive fill material 6030, as is depicted inFIGS. 60A-60C. In another embodiment, individual ones of the pluralityof conductive interconnect lines 6006 include a barrier layer 6028 alongsidewalls and a bottom of a conductive fill material 6030, and recessingthe plurality of conductive interconnect lines includes recessing theconductive fill material 6030 but not substantially recessing thebarrier layer 6028, as is depicted in FIG. 60D. In an embodiment, theetch-stop layer 6012 re-directs a lithographically mis-aligned viatrench pattern. In an embodiment, recessing the plurality of conductiveinterconnect lines includes recessing by an amount in the range of0.5-1.5 nanometers relative to the first ILD layer 6004.

In a second example of etch stop layer topography, FIGS. 61A-61Dillustrate cross-sectional views of structural arrangements for astepped line topography of a BEOL metallization layer, in accordancewith an embodiment of the present disclosure.

Referring to FIG. 61A, an integrated circuit structure 6100 includes aplurality of conductive interconnect lines 6106 in and spaced apart byan inter-layer dielectric (ILD) layer 6104 above a substrate 6102. Oneof the plurality of conductive interconnect lines 6106 is shown ascoupled to an underlying via 6107 for exemplary purposes. Individualones of the plurality of conductive interconnect lines 6106 have anupper surface 6108 above an upper surface 6110 of the ILD layer 6104. Anetch-stop layer 6112 is on and conformal with the ILD layer 6104 and theplurality of conductive interconnect lines 6106. The etch-stop layer6112 has a non-planar upper surface with a lowermost portion 6114 of thenon-planar upper surface over the ILD layer 6104 and an uppermostportion 6116 of the non-planar upper surface over the plurality ofconductive interconnect lines 6106.

A conductive via 6118 is on and electrically coupled to an individualone 6106A of the plurality of conductive interconnect lines 6106. Theconductive via 6118 is in an opening 6120 of the etch-stop layer 6112.The opening 6120 is over the individual one 6106A of the plurality ofconductive interconnect lines 6106 but not over the ILD layer 6114. Theconductive via 6118 is in a second ILD layer 6122 above the etch-stoplayer 6112. In one embodiment, the second ILD layer 6122 is on andconformal with the etch-stop layer 6112, as is depicted in FIG. 61A.

In an embodiment, a center 6124 of the conductive via 6118 is alignedwith a center 6126 of the individual one 6106A of the plurality ofconductive interconnect lines 6106, as is depicted in FIG. 61A. Inanother embodiment, however, a center 6124 of the conductive via 6118 isoff-set from a center 6126 of the individual one 6106A of the pluralityof conductive interconnect lines 6106, as is depicted in FIG. 61B.

In an embodiment, individual ones of the plurality of conductiveinterconnect lines 6106 include a barrier layer 6128 along sidewalls anda bottom of a conductive fill material 6130. In one embodiment, both thebarrier layer 6128 and the conductive fill material 6130 have anuppermost surface above the upper surface 6110 of the ILD layer 6104, asis depicted in FIGS. 61A, 61B and 61C. In a particular such embodiment,the uppermost surface of the barrier layer 6128 is below the uppermostsurface of the conductive fill material 6130, as is depicted in FIG.61C. In another embodiment, the conductive fill material 6130 has anuppermost surface above the upper surface 6110 of the ILD layer 6104,and the barrier layer 6128 has an uppermost surface co-planar with theupper surface 6110 of the ILD layer 6104, as is depicted in FIG. 61D.

In an embodiment, the ILD layer 6104 includes silicon, carbon andoxygen, and the etch-stop layer 6112 includes silicon and nitrogen. Inan embodiment, the upper surface 6108 of the individual ones of theplurality of conductive interconnect lines 6106 is above the uppersurface 6110 of the ILD layer 6004 by an amount in the range of 0.5-1.5nanometers.

Referring collectively to FIGS. 61A-61D, in accordance with anembodiment of the present disclosure, a method of fabricating anintegrated circuit structure includes forming a plurality of conductiveinterconnect lines 6106 in and spaced apart by a first inter-layerdielectric (ILD) layer above a substrate 6102. The first ILD layer 6104is recessed relative to the plurality of conductive interconnect lines6106 to provide individual ones of the plurality of conductiveinterconnect lines 6106 having an upper surface 6108 above an uppersurface 6110 of the first ILD layer 6104. Subsequent to recessing thefirst ILD layer 6104, an etch-stop layer 6112 is formed on and conformalwith the first ILD layer 6104 and the plurality of conductiveinterconnect lines 6106. The etch-stop layer 6112 has a non-planar uppersurface with a lowermost portion 6114 of the non-planar upper surfaceover the first ILD layer 6104 and an uppermost portion 6116 of thenon-planar upper surface over the plurality of conductive interconnectlines 6106. A second ILD layer 6122 is formed on the etch-stop layer6112. A via trench is etched in the second ILD layer 6122. The etch-stoplayer 6112 directs the location of the via trench in the second ILDlayer 6122 during the etching. The etch-stop layer 6112 is etchedthrough the via trench to form an opening 6120 in the etch-stop layer6112. The opening 6120 is over an individual one 6106A of the pluralityof conductive interconnect lines 6106 but not over the first ILD layer6104. A conductive via 6118 is formed in the via trench and in theopening 6120 in the etch-stop layer 6112. The conductive via 6118 is onand electrically coupled to the individual one 6106A of the plurality ofconductive interconnect lines 6106.

In one embodiment, individual ones of the plurality of conductiveinterconnect lines 6106 include a barrier layer 6128 along sidewalls anda bottom of a conductive fill material 6130, and recessing the first ILDlayer 6104 includes recessing relative to both the barrier layer 6128and the conductive fill material 6130, as is depicted in FIGS. 61A-61C.In another embodiment, individual ones of the plurality of conductiveinterconnect lines 6106 include a barrier layer 6128 along sidewalls anda bottom of a conductive fill material 6130, and recessing the first ILDlayer 6104 includes recessing relative to the conductive fill material6130 but not relative to the barrier layer 6128, as is depicted in FIG.61D. In an embodiment, wherein the etch-stop layer 6112 re-directs alithographically mis-aligned via trench pattern. In an embodiment,recessing the first ILD layer 6104 includes recessing by an amount inthe range of 0.5-1.5 nanometers relative to the plurality of conductiveinterconnect lines 6106.

In another aspect, techniques for patterning metal line ends aredescribed. To provide context, in the advanced nodes of semiconductormanufacturing, lower level interconnects may created by separatepatterning processes of the line grating, line ends, and vias. However,the fidelity of the composite pattern may tend to degrade as the viasencroach upon the line ends and vice-versa. Embodiments described hereinprovide for a line end process also known as a plug process thateliminates associated proximity rules. Embodiments may allow for a viato be placed at the line end and a large via to strap across a line end.

To provide further context, FIG. 62A illustrates a plan view andcorresponding cross-sectional view taken along the a-a′ axis of the planview of a metallization layer, in accordance with an embodiment of thepresent disclosure. FIG. 62B illustrates a cross-sectional view of aline end or plug, in accordance with an embodiment of the presentdisclosure. FIG. 62C illustrates another cross-sectional view of a lineend or plug, in accordance with an embodiment of the present disclosure.

Referring to FIG. 62A, a metallization layer 6200 includes metal lines6202 formed in a dielectric layer 6204. The metal lines 6202 may becoupled to underlying vias 6203. The dielectric layer 6204 may includeline end or plug regions 6205. Referring to FIG. 62B, a line end or plugregion 6205 of a dielectric layer 6204 may be fabricated by patterning ahardmask layer 6210 on the dielectric layer 6204 and then etchingexposed portions of the dielectric layer 6204. The exposed portions ofthe dielectric layer 6204 may be etched to a depth suitable to form aline trench 6206 or further etched to a depth suitable to form a viatrench 6208. Referring to FIG. 62C, two vias adjacent opposing sidewallsof the line end or plug 6205 may be fabricated in a single largeexposure 6216 to ultimately form line trenches 6212 and via trenches6214.

However, referring again to FIGS. 62A-62C, fidelity issues and/orhardmask erosion issues may lead to imperfect patterning regimes. Bycontrast, one or more embodiments described herein includeimplementation of a process flow involving construction of a line enddielectric (plug) after a trench and via patterning process.

In an aspect, then, one or more embodiments described herein aredirected to approaches for building non-conductive spaces orinterruptions between metals lines (referred to as “line ends,” “plugs”or “cuts”) and, in some embodiments, associated conductive vias.Conductive vias, by definition, are used to land on a previous layermetal pattern. In this vein, embodiments described herein enable a morerobust interconnect fabrication scheme since alignment by lithographyequipment is relied on to a lesser extent. Such an interconnectfabrication scheme can be used to relax constraints onalignment/exposures, can be used to improve electrical contact (e.g., byreducing via resistance), and can be used to reduce total processoperations and processing time otherwise required for patterning suchfeatures using conventional approaches.

FIGS. 63A-63F illustrate plan views and corresponding cross-sectionalviews representing various operations in a plug last processing scheme,in accordance with an embodiment of the present disclosure.

Referring to FIG. 63A, a method of fabricating an integrated circuitstructure includes forming a line trench 6306 in an upper portion 6304of an interlayer dielectric (ILD) material layer 6302 formed above anunderlying metallization layer 6300. A via trench 6308 is formed in alower portion 6310 of the ILD material layer 6302. The via trench 6308exposes a metal line 6312 of the underlying metallization layer 6300.

Referring to FIG. 63B, a sacrificial material 6314 is formed above theILD material layer 6302 and in the line trench 6306 and the via trench6308. The sacrificial material 6314 may have a hardmask 6315 formedthereon, as is depicted in FIG. 63B. In one embodiment, the sacrificialmaterial 6314 includes carbon.

Referring to FIG. 63C, the sacrificial material 6314 is patterned tobreak a continuity of the sacrificial material 6314 in the line trench6306, e.g., to provide an opening 6316 in the sacrificial material 6314.

Referring to FIG. 63D, the opening 6316 in the sacrificial material 6314is filled with a dielectric material to form a dielectric plug 6318. Inan embodiment, subsequent to filling the opening 6316 in the sacrificialmaterial 6314 with the dielectric material, the hardmask 6315 is removedto provide the dielectric plug 6318 having an upper surface 6320 abovean upper surface 6322 of the ILD material 6302, as is depicted in FIG.63D. The sacrificial material 6314 is removed to leave the dielectricplug 6318 to remain.

In an embodiment, filling the opening 6316 of the sacrificial material6314 with the dielectric material includes filling with a metal oxidematerial. In one such embodiment, the metal oxide material is aluminumoxide. In an embodiment, filling the opening 6314 of the sacrificialmaterial 6316 with the dielectric material includes filling using atomiclayer deposition (ALD).

Referring to FIG. 63E, the line trench 6306 and the via trench 6308 arefilled with a conductive material 6324. In an embodiment, the conductivematerial 6324 is formed above and over the dielectric plug 6318 and theILD layer 6302, as is depicted.

Referring to FIG. 63F, the conductive material 6324 and the dielectricplug 6318 are planarized to provide a planarized dielectric plug 6318′breaking a continuity of the conductive material 6324 in the line trench6306.

Referring again to FIG. 63F, in an accordance with an embodiment of thepresent disclosure, an integrated circuit structure 6350 includes aninter-layer dielectric (ILD) layer 6302 above a substrate. A conductiveinterconnect line 6324 is in a trench 6306 in the ILD layer 6302. Theconductive interconnect line 6324 has a first portion 6324A and a secondportion 6324B, the first portion 6324A laterally adjacent to the secondportion 6324B. A dielectric plug 6318′ is between and laterally adjacentto the first 6324A and second 6324B portions of the conductiveinterconnect line 6324. Although not depicted, in an embodiment, theconductive interconnect line 6324 includes a conductive barrier linerand a conductive fill material, exemplary materials for which aredescribed above. In one such embodiment, the conductive fill materialincludes cobalt.

In an embodiment, the dielectric plug 6318′ includes a metal oxidematerial. In one such embodiment, the metal oxide material is aluminumoxide. In an embodiment, the dielectric plug 6318′ is in direct contactwith the first 6324A and second 6324B portions of the conductiveinterconnect line 6324.

In an embodiment, the dielectric plug 6318′ has a bottom 6318Asubstantially co-planar with a bottom 6324C of the conductiveinterconnect line 6324. In an embodiment, a first conductive via 6326 isin a trench 6308 in the ILD layer 6302. In one such embodiment, thefirst conductive via 6326 is below the bottom 6324C of the interconnectline 6324, and the first conductive via 6326 is electrically coupled tothe first portion 6324A of the conductive interconnect line 6324.

In an embodiment, a second conductive via 6328 is in a third trench 6330in the ILD layer 6302. The second conductive via 6328 is below thebottom 6324C of the interconnect line 6324, and the second conductivevia 6328 is electrically coupled to the second portion 6324B of theconductive interconnect line 6324.

A dielectric plug may be formed using a fill process such as a chemicalvapor deposition process. Artifacts may remain in the fabricateddielectric plug. As an example, FIG. 64A illustrates a cross-sectionalview of a conductive line plug having a seam therein, in accordance withan embodiment of the present disclosure.

Referring to FIG. 64A, a dielectric plug 6418 has an approximatelyvertical seam 6400 spaced approximately equally from the first portion6324A of the conductive interconnect line 6324 and from the secondportion 6324B of the conductive interconnect line 6324.

It is to be appreciated that dielectric plugs differing in compositionfrom an ILD material in which they are housed may be included on onlyselect metallization layers, such as in lower metallization layers. Asan example, FIG. 64B illustrates a cross-sectional view of a stack ofmetallization layers including a conductive line plug at a lower metalline location, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 64B, an integrated circuit structure 6450 includes afirst plurality of conductive interconnect lines 6456 in and spacedapart by a first inter-layer dielectric (ILD) layer 6454 above asubstrate 6452. Individual ones of the first plurality of conductiveinterconnect lines 6456 have a continuity broken by one or moredielectric plugs 6458. In an embodiment, the one or more dielectricplugs 6458 include a material different than the ILD layer 6452. Asecond plurality of conductive interconnect lines 6466 is in and spacedapart by a second ILD layer 6464 above the first ILD layer 6454. In anembodiment, individual ones of the second plurality of conductiveinterconnect lines 6466 have a continuity broken by one or more portions6468 of the second ILD layer 6464. It is to be appreciated, as depicted,that other metallization layers may be included in the integratedcircuit structure 6450.

In one embodiment, the one or more dielectric plugs 6458 include a metaloxide material. In one such embodiment, the metal oxide material isaluminum oxide. In one embodiment, the first ILD layer 6454 and thesecond ILD layer 6464 (and, hence, the one or more portions 6568 of thesecond ILD layer 6464) include a carbon-doped silicon oxide material.

In one embodiment, individual ones of the first plurality of conductiveinterconnect lines 6456 include a first conductive barrier liner 6456Aand a first conductive fill material 6456B. Individual ones of thesecond plurality of conductive interconnect lines 6466 include a secondconductive barrier liner 6466A and a second conductive fill material6466B. In one such embodiment, the first conductive fill material 6456Bis different in composition from the second conductive fill material6466B. In a particular such embodiment, the first conductive fillmaterial 6456B includes cobalt, and the second conductive fill material6466B includes copper.

In one embodiment, the first plurality of conductive interconnect lines6456 has a first pitch (P1, as shown in like-layer 6470). The secondplurality of conductive interconnect lines 6466 has a second pitch (P2,as shown in like-layer 6480). The second pitch (P2) is greater than thefirst pitch (P1). In one embodiment, individual ones of the firstplurality of conductive interconnect lines 6456 have a first width (W1,as shown in like-layer 6470). Individual ones of the second plurality ofconductive interconnect lines 6466 have a second width (W2, as shown inlike-layer 6480). The second width (W2) is greater than the first width(W1).

It is to be appreciated that the layers and materials described above inassociation with back end of line (BEOL) structures and processing maybe formed on or above an underlying semiconductor substrate orstructure, such as underlying device layer(s) of an integrated circuit.In an embodiment, an underlying semiconductor substrate represents ageneral workpiece object used to manufacture integrated circuits. Thesemiconductor substrate often includes a wafer or other piece of siliconor another semiconductor material. Suitable semiconductor substratesinclude, but are not limited to, single crystal silicon, polycrystallinesilicon and silicon on insulator (SOI), as well as similar substratesformed of other semiconductor materials, such as substrates includinggermanium, carbon, or group III-V materials. The semiconductorsubstrate, depending on the stage of manufacture, often includestransistors, integrated circuitry, and the like. The substrate may alsoinclude semiconductor materials, metals, dielectrics, dopants, and othermaterials commonly found in semiconductor substrates. Furthermore, thestructures depicted may be fabricated on underlying lower levelinterconnect layers.

Although the preceding methods of fabricating a metallization layer, orportions of a metallization layer, of a BEOL metallization layer aredescribed in detail with respect to select operations, it is to beappreciated that additional or intermediate operations for fabricationmay include standard microelectronic fabrication processes such aslithography, etch, thin films deposition, planarization (such aschemical mechanical polishing (CMP)), diffusion, metrology, the use ofsacrificial layers, the use of etch stop layers, the use ofplanarization stop layers, or any other associated action withmicroelectronic component fabrication. Also, it is to be appreciatedthat the process operations described for the preceding process flowsmay be practiced in alternative sequences, not every operation need beperformed or additional process operations may be performed or both.

In an embodiment, as used throughout the present description, interlayerdielectric (ILD) material is composed of or includes a layer of adielectric or insulating material. Examples of suitable dielectricmaterials include, but are not limited to, oxides of silicon (e.g.,silicon dioxide (SiO₂)), doped oxides of silicon, fluorinated oxides ofsilicon, carbon doped oxides of silicon, various low-k dielectricmaterials known in the arts, and combinations thereof. The interlayerdielectric material may be formed by techniques, such as, for example,chemical vapor deposition (CVD), physical vapor deposition (PVD), or byother deposition methods.

In an embodiment, as is also used throughout the present description,metal lines or interconnect line material (and via material) is composedof one or more metal or other conductive structures. A common example isthe use of copper lines and structures that may or may not includebarrier layers between the copper and surrounding ILD material. As usedherein, the term metal includes alloys, stacks, and other combinationsof multiple metals. For example, the metal interconnect lines mayinclude barrier layers (e.g., layers including one or more of Ta, TaN,Ti or TiN), stacks of different metals or alloys, etc. Thus, theinterconnect lines may be a single material layer, or may be formed fromseveral layers, including conductive liner layers and fill layers. Anysuitable deposition process, such as electroplating, chemical vapordeposition or physical vapor deposition, may be used to forminterconnect lines. In an embodiment, the interconnect lines arecomposed of a conductive material such as, but not limited to, Cu, Al,Ti, Zr, Hf, V, Ru, Co, Ni, Pd, Pt, W, Ag, Au or alloys thereof. Theinterconnect lines are also sometimes referred to in the art as traces,wires, lines, metal, or simply interconnect.

In an embodiment, as is also used throughout the present description,hardmask materials are composed of dielectric materials different fromthe interlayer dielectric material. In one embodiment, differenthardmask materials may be used in different regions so as to providedifferent growth or etch selectivity to each other and to the underlyingdielectric and metal layers. In some embodiments, a hardmask layerincludes a layer of a nitride of silicon (e.g., silicon nitride) or alayer of an oxide of silicon, or both, or a combination thereof. Othersuitable materials may include carbon-based materials. In anotherembodiment, a hardmask material includes a metal species. For example, ahardmask or other overlying material may include a layer of a nitride oftitanium or another metal (e.g., titanium nitride). Potentially lesseramounts of other materials, such as oxygen, may be included in one ormore of these layers. Alternatively, other hardmask layers known in thearts may be used depending upon the particular implementation. Thehardmask layers maybe formed by CVD, PVD, or by other depositionmethods.

In an embodiment, as is also used throughout the present description,lithographic operations are performed using 193 nm immersion lithography(i193), extreme ultra-violet (EUV) lithography or electron beam directwrite (EBDW) lithography, or the like. A positive tone or a negativetone resist may be used. In one embodiment, a lithographic mask is atrilayer mask composed of a topographic masking portion, ananti-reflective coating (ARC) layer, and a photoresist layer. In aparticular such embodiment, the topographic masking portion is a carbonhardmask (CHM) layer and the anti-reflective coating layer is a siliconARC layer.

In another aspect, one or more embodiments described herein are directedto memory bit cells having an internal node jumper. Particularembodiments may include a layout-efficient technique of implementingmemory bit cells in advanced self-aligned process technologies.Embodiments may be directed to 10 nanometer or smaller technology nodes.Embodiments may provide an ability to develop memory bit cells havingimproved performance within a same footprint by utilizing contact overactive gate (COAG) or aggressive metal 1 (M1) pitch scaling, or both.Embodiments may include or be directed to bit cell layouts that makepossible higher performance bit cells in a same or smaller footprintrelative to a previous technology node.

In accordance with an embodiment of the present disclosure, a highermetal layer (e.g., metal1 or M1) jumper is implemented to connectinternal nodes rather than the use of a traditional gate-trenchcontact-gate contact (poly-tcn-polycon) connection. In an embodiment, acontact over active gate (COAG) integration scheme combined with a metal1 jumper to connect internal nodes mitigates or altogether eliminatesthe need to grow a footprint for a higher performance bit cell. That is,an improved transistor ratio may be achieved. In an embodiment, such anapproach enables aggressive scaling to provide improved cost pertransistor for, e.g., a 10 nanometer (10 nm) technology node. Internalnode M1 jumpers may be implemented in SRAM, RF and Dual Port bit cellsin 10 nm technology to produce very compact layouts.

As a comparative example, FIG. 65 illustrates a first view of a celllayout for a memory cell.

Referring to FIG. 65, an exemplary 14 nanometer (14 nm) layout 6500includes a bit cell 6502. Bit cell 6502 includes gate or poly lines 6504and metal 1 (M1) lines 6506. In the example shown, the poly lines 6504have a 1× pitch, and the M1 lines 6506 have a 1× pitch. In a particularembodiment, the poly lines 6504 have 70 nm pitch, and the M1 lines 6506have a 70 nm pitch.

In contrast to FIG. 65, FIG. 66 illustrates a first view of a celllayout for a memory cell having an internal node jumper, in accordancewith an embodiment of the present disclosure.

Referring to FIG. 66, an exemplary 10 nanometer (10 nm) layout 6600includes a bit cell 6602. Bit cell 6602 includes gate or poly lines 6604and metal 1 (M1) lines 6606. In the example shown, the poly lines 6604have 1× pitch, and the M1 lines 6606 have a 0.67× pitch. The result isan overlapping line 6605, which includes a M1 line directly over a polyline. In a particular embodiment, the poly lines 6604 have 54 nm pitch,and the M1 lines 6606 have a 36 nm pitch.

In comparison to layout 6500, in layout 6600, the M1 pitch is less thanthe gate pitch, freeing up an extra line (6605) every third line (e.g.,for every two poly lines, there are three M1 lines). The “freed up” M1line is referred to herein as an internal node jumper. The internal nodejumper may be used for gate to gate (poly to poly) interconnection orfor trench contact to trench contact interconnection. In an embodiment,contact to poly is achieved through a contact over active gate (COAG)arrangement, enabling fabrication of the internal node jumper.

Referring more generally to FIG. 66, in an embodiment, an integratedcircuit structure includes a memory bit cell 6602 on a substrate. Thememory bit cell 6602 includes first and second gate lines 6604 parallelalong a second direction 2 of the substrate. The first and second gatelines 6602 have a first pitch along a first direction (1) of thesubstrate, the first direction (1) perpendicular to the second direction(2). First, second and third interconnect lines 6606 are over the firstand second gate lines 6604. The first, second and third interconnectlines 6606 are parallel along the second direction (2) of the substrate.The first, second and third interconnect lines 6606 have a second pitchalong the first direction, where the second pitch is less than the firstpitch. In one embodiment, one of the first, second and thirdinterconnect lines 6606 is an internal node jumper for the memory bitcell 6602.

As is applicable throughout the present disclosure, the gate lines 6604may be referred to as being on tracks to form a grating structure.Accordingly, the grating-like patterns described herein may have gatelines or interconnect lines spaced at a constant pitch and having aconstant width. The pattern may be fabricated by a pitch halving orpitch quartering, or other pitch division, approach.

As a comparative example, FIG. 67 illustrates a second view of a celllayout 6700 for a memory cell.

Referring to FIG. 67, the 14 nm bit cell 6502 is shown with N-diffusion6702 (e.g., P-type doped active regions, such as boron doped diffusionregions of an underlying substrate) and P-diffusion 6704 (e.g., N-typedoped active regions, such as phosphorous or arsenic, or both, dopeddiffusion regions of an underlying substrate) with M1 lines removed forclarity. Layout 6700 of bit cell 102 includes gate or poly lines 6504,trench contacts 6706, gate contacts 6708 (specific for 14 nm node) andcontact vias 6710.

In contrast to FIG. 67, FIG. 68 illustrates a second view of a celllayout 6800 for a memory cell having an internal node jumper, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 68, the 10 nm bit cell 6602 is shown with N-diffusion6802 (e.g., P-type doped active regions, such as boron doped diffusionregions of an underlying substrate) and P-diffusion 6804 (e.g., N-typedoped active regions, such as phosphorous or arsenic, or both, dopeddiffusion regions of an underlying substrate) with M1 lines removed forclarity. Layout 6800 of bit cell 202 includes gate or poly lines 6604,trench contacts 6806, gate vias 6808 (specific for 10 nm node) andtrench contact vias 6710.

In comparing layouts 6700 and 6800, in accordance with an embodiment ofthe present disclosure, in the 14 nm layout the internal nodes areconnected by a gate contact (GCN) only. An enhanced performance layoutcannot be created in the same footprint due to poly to GCN spaceconstraints. In the 10 nm layout, the design allows for landing acontact (VCG) on the gate to eliminate the need for a poly contact. Inone embodiment, the arrangement enabled connection of an internal nodeusing Ml, allowing for addition active region density (e.g., increasednumber of fins) within the 14 nm footprint. In the 10 nm layout, uponusing a COAG architecture, spacing between diffusion regions can be madesmaller since they are not limited by trench contact to gate contactspacing. In an embodiment, the layout 6700 of FIG. 67 is referred to asa 112 (1 fin pull-up, 1 fin pass gate, 2 fin pull down) arrangement. Bycontrast, the layout 6800 of FIG. 68 is referred to as a 122 (1 finpull-up, 2 fin pass gate, 2 fin pull down) arrangement that, in aparticular embodiment, is within the same footprint as the 112 layout ofFIG. 67. In an embodiment, the 122 arrangement provides improvedperformance as compared with the 112 arrangement.

As a comparative example, FIG. 69 illustrates a third view of a celllayout 6900 for a memory cell.

Referring to FIG. 69, the 14 nm bit cell 6502 is shown with metal 0 (M0)lines 6902 with poly lines removed for clarity. Also shown are metal 1(M1) lines 6506, contact vias 6710, via 0 structures 6904.

In contrast to FIG. 69, FIG. 70 illustrates a third view of a celllayout 7000 for a memory cell having an internal node jumper, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 70, the 10 nm bit cell 6602 is shown with metal 0 (M0)lines 7002 with poly lines removed for clarity. Also shown are metal 1(M1) lines 6606, gate vias 6808, trench contact vias 6810, and via 0structures 7004. In comparing FIGS. 69 and 70, in accordance with anembodiment of the present disclosure, for the 14 nm layout the internalnodes are connected by gate contact (GCN) only, while for the 10 nmlayout one of the internal nodes is connected using a M1 jumper.

Referring to FIGS. 66, 68 and 70 collectively, in accordance with anembodiment of the present disclosure, an integrated circuit structureincludes a memory bit cell 6602 on a substrate. The memory bit cell 6602includes first (top 6802), second (top 6804), third (bottom 6804) andfourth (bottom 6802) active regions parallel along a first direction (1)of the substrate. First (left 6604) and second (right 6604) gate linesare over the first, second, third and fourth active regions 6802/6804.The first and second gate lines 6604 are parallel along a seconddirection (2) of the substrate, the second direction (2) perpendicularto the first direction (1). First (far left 6606), second (near left6606) and third (near right 6606) interconnect lines are over the firstand second gate lines 6604. The first, second and third interconnectlines 6606 are parallel along the second direction (2) of the substrate.

In an embodiment, the first (far left 6606) and second (near left 6606)interconnect lines are electrically connected to the first and secondgate lines 6604 at locations of the first and second gate lines 6604over one or more of the first, second, third and fourth active regions6802/6804 (e.g., at so-called “active gate” locations). In oneembodiment, the first (far left 6606) and second (near left 6606)interconnect lines are electrically connected to the first and secondgate lines 6604 by an intervening plurality of interconnect lines 7004vertically between the first and second interconnect lines 6606 and thefirst and second gate lines 6604. The intervening plurality ofinterconnect lines 7004 is parallel along the first direction (1) of thesubstrate.

In an embodiment, the third interconnect line (near right 6606)electrically couples together a pair of gate electrodes of the memorybit cell 6602, the pair of gate electrodes included in the first andsecond gate lines 6604. In another embodiment, the third interconnectline (near right 6606) electrically couples together a pair of trenchcontacts of the memory bit cell 6602, the pair of trench contactsincluded in a plurality of trench contact lines 6806. In an embodiment,the third interconnect line (near right 6606) is an internal nodejumper.

In an embodiment, the first active region (top 6802) is a P-type dopedactive region (e.g., to provide N-diffusion for an NMOS device), thesecond active region (top 6804) is an N-type doped active region (e.g.,to provide P-diffusion for a PMOS device), the third active region(bottom 6804) is an N-type doped active region (e.g., to provideP-diffusion for a PMOS device), and the fourth active region (bottom6802) is an N-type doped active region (e.g., to provide N-diffusion foran NMOS device). In an embodiment, the first, second, third and fourthactive regions 6802/6804 are in silicon fins. In an embodiment, thememory bit cell 6602 includes a pull-up transistor based on a singlesilicon fin, a pass-gate transistor based on two silicon fins, and apull-down transistor based on two silicon fins.

In an embodiment, the first and second gate lines 6604 alternate withindividual ones of a plurality of trench contact lines 6806 parallelalong the second direction (2) of the substrate. The plurality of trenchcontact lines 6806 includes trench contacts of the memory bit cell 6602.The first and second gate lines 6604 include gate electrode of thememory bit cell 6602.

In an embodiment, the first and second gate lines 6604 have a firstpitch along the first direction (1). The first, second and thirdinterconnect lines 6606 have a second pitch along the first direction(2). In one such embodiment, the second pitch is less than the firstpitch. In a specific such embodiment, the first pitch is in the range of50 nanometers to 60 nanometers, and the second pitch is in the range of30 nanometers to 40 nanometers. In a particular such embodiment, thefirst pitch is 54 nanometers, and the second pitch is 36 nanometers.

Embodiments described herein may be implemented to provide an increasednumber of fins within a relatively same bit cell footprint as a previoustechnology node, enhancing the performance of a smaller technology nodememory bit cell relative to that of a previous generation. As anexample, FIGS. 71A and 71B illustrate a bit cell layout and a schematicdiagram, respectively, for a six transistor (6T) static random accessmemory (SRAM), in accordance with an embodiment of the presentdisclosure.

Referring to FIGS. 71A and 71B, a bit cell layout 7102 includes thereingate lines 7104 (which may also be referred to as poly lines) parallelalong direction (2). Trench contact lines 7106 alternate with the gatelines 7104. The gate lines 7104 and trench contact lines 7106 are overNMOS diffusion regions 7108 (e.g., P-type doped active regions, such asboron doped diffusion regions of an underlying substrate) and PMOSdiffusion regions 7110 (e.g., N-type doped active regions, such asphosphorous or arsenic, or both, doped diffusion regions of anunderlying substrate) which are parallel along direction (1). In anembodiment, both of the NMOS diffusion regions 7108 each includes twosilicon fins. Both of the PMOS diffusion regions 7110 each includes onesilicon fin.

Referring again to FIGS. 71A and 71B, NMOS pass gate transistors 7112,NMOS pull-down transistors 7114, and PMOS pull-up transistors 7116 areformed from the gate lines 7104 and the NMOS diffusion regions 7108 andthe PMOS diffusion regions 7110. Also depicted are a wordline (WL) 7118,internal nodes 7120 and 7126, a bit line (BL) 7122, a bit line bar (BLB)7124, SRAM VCC 7128, and VSS 7130.

In an embodiment, contact to the first and second gate lines 7104 of thebit cell layout 7102 is made to active gate locations of the first andsecond gate lines 7104. In an embodiment, the 6T SRAM bit cell 7104includes an internal node jumper, such as described above.

In an embodiment, layouts described herein are compatible with uniformplug and mask patterns, including a uniform fin trim mask. Layouts maybe compatible with non-EUV processes. Additionally, layouts may onlyrequire use of a middle-fin trim mask. Embodiments described herein mayenable increased density in terms of area compared to other layouts.Embodiments may be implemented to provide a layout-efficient memoryimplementation in advanced self-aligned process technologies. Advantagesmay be realized in terms of die area or memory performance, or both.Circuit techniques may be uniquely enabled by such layout approaches.

One or more embodiments described herein are directed to multi versionlibrary cell handling when parallel interconnect lines (e.g., Metal 1lines) and gate lines are misaligned. Embodiments may be directed to 10nanometer or smaller technology nodes. Embodiments may include or bedirected to cell layouts that make possible higher performance cells ina same or smaller footprint relative to a previous technology node. Inan embodiment, interconnect lines overlying gate lines are fabricated tohave an increased density relative to the underlying gate lines. Such anembodiment may enable an increase in pin hits, increased routingpossibilities, or increased access to cell pins. Embodiments may beimplemented to provide greater than 6% block level density.

To provide context, gate lines and the next parallel level ofinterconnects (typically referred to as metal 1, with a metal 0 layerrunning orthogonal between metal 1 and the gate lines) need to be inalignment at the block level. However, in an embodiment, the pitch ofthe metal 1 lines is made different, e.g., smaller, than the pitch ofthe gate lines. Two standard cell versions (e.g., two different cellpatterns) for each cell are made available to accommodate the differencein pitch. The particular version selected follows a rule placementadhering at the block level. If not selected properly, dirtyregistration (DR) may occur. In accordance with an embodiment of thepresent disclosure, a higher metal layer (e.g., metal 1 or M1) withincreased pitch density relative to the underlying gate lines isimplemented. In an embodiment, such an approach enables aggressivescaling to provide improved cost per transistor for, e.g., a 10nanometer (10 nm) technology node.

FIG. 72 illustrates cross-sectional views of two different layouts for asame standard cell, in accordance with an embodiment of the presentdisclosure.

Referring to part (a) of FIG. 72, a set of gate lines 7204A overlies asubstrate 7202A. A set of metal 1 (M1) interconnects 7206A overlies theset of gate lines 7204A. The set of metal 1 (M1) interconnects 7206A hasa tighter pitch than the set of gate lines 7204A. However, the outermostmetal 1 (M1) interconnects 7206A have outer alignment with the outermostgate lines 7204A. For designation purposes, as used throughout thepresent disclosure, the aligned arrangement of part (a) of FIG. 72 isreferred to as having even (E) alignment.

In contrast to part (a), referring to part (b) of FIG. 72, a set of gatelines 7204B overlies a substrate 7202B. A set of metal 1 (M1)interconnects 7206B overlies the set of gate lines 7204B. The set ofmetal 1 (M1) interconnects 7206B has a tighter pitch than the set ofgate lines 7204B. The outermost metal 1 (M1) interconnects 7206B do nothave outer alignment with the outermost gate lines 7204B. Fordesignation purposes, as used throughout the present disclosure, thenon-aligned arrangement of part (b) of FIG. 72 is referred to as havingodd (O) alignment.

FIG. 73 illustrates plan views of four different cell arrangementsindicating the even (E) or odd (O) designation, in accordance with anembodiment of the present disclosure.

Referring to part (a) of FIG. 73, a cell 7300A has gate (or poly) lines7302A and metal 1 (M1) lines 7304A. The cell 7300A is designated as anEE cell since the left side of cell 7300A and right side of cell 7300Ahave aligned gate 7302A and M1 7304A lines. By contrast, referring topart (b) of FIG. 73, a cell 7300B has gate (or poly) lines 7302B andmetal 1 (M1) lines 7304B. The cell 7300B is designated as an 00 cellsince the left side of cell 7300B and right side of cell 7300B havenon-aligned gate 7302B and M1 7304B lines.

Referring to part (c) of FIG. 73, a cell 7300C has gate (or poly) lines7302C and metal 1 (M1) lines 7304C. The cell 7300C is designated as anEO cell since the left side of cell 7300C has aligned gate 7302C and M17304C lines, but the right side of cell 7300C has non-aligned gate 7302Cand M1 7304C lines. By contrast, referring to part (d) of FIG. 73, acell 7300D has gate (or poly) lines 7302D and metal 1 (M1) lines 7304D.The cell 7300D is designated as an OE cell since the left side of cell7300D has non-aligned gate 7302D and M1 7304D lines, but the right sideof cell 7300D has aligned gate 7302D and M1 7304D lines.

As a foundation for placing selected first or second versions ofstandard cell types, FIG. 74 illustrates a plan view of a block levelpoly grid, in accordance with an embodiment of the present disclosure.Referring to FIG. 74, a block level poly grid 7400 includes gate lines7402 running parallel along a direction 7404. Designated cell layoutborders 7406 and 7408 are shown running in a second, orthogonaldirection. The gate lines 7402 alternate between even (E) and odd (O)designation.

FIG. 75 illustrates an exemplary acceptable (pass) layout based onstandard cells having different versions, in accordance with anembodiment of the present disclosure. Referring to FIG. 75, a layout7500 includes three cells of the type 7300C/7300D as placed in orderfrom left to right between borders 7406 and 7408: 7300D, abutting first7300C and spaced apart second 7300C. The selection between 7300C and7300D is based on the alignment of the E or O designations on thecorresponding gate lines 7402. The layout 7500 also includes cells ofthe type 7300A/7300B as placed in order from left to right below border7408: first 7300A spaced apart from second 7300A. The selection between7300A and 7300B is based on the alignment of the E or O designations onthe corresponding gate lines 7402. Layout 7500 is a pass cell in thesense that no dirty registration (DR) occurs in the layout 7500. It isto be appreciated that p designates power, and a, b, c or o areexemplary pins. In the arrangement 7500 the power lines p line up withone another across border 7408.

Referring more generally to FIG. 75, in accordance with an embodiment ofthe present disclosure, an integrated circuit structure includes aplurality of gate lines 7402 parallel along a first direction of asubstrate and having a pitch along a second direction orthogonal to thefirst direction. A first version 7300C of a cell type is over a firstportion of the plurality of gate lines 7402. The first version 7300C ofthe cell type includes a first plurality of interconnect lines having asecond pitch along the second direction, the second pitch less than thefirst pitch. A second version 7300D of the cell type is over a secondportion of the plurality of gate lines 7402 laterally adjacent to thefirst version 7300C of the cell type along the second direction. Thesecond version 7300D of the cell type includes a second plurality ofinterconnect lines having the second pitch along the second direction.The second version 7300D of the cell type is structurally different thanthe first version 7300C of the cell type.

In an embodiment, individual ones of the first plurality of interconnectlines of the first version 7300C of the cell type align with individualones of the plurality of gate lines 7402 along the first direction at afirst edge (e.g., left edge) but not at a second edge (e.g., right edge)of the first version 7300C of the cell type along the second direction.In one such embodiment, the first version of the cell type 7300C is afirst version of a NAND cell. Individual ones of the second plurality ofinterconnect lines of the second version 7300D of the cell type do notalign with individual ones of the plurality of gate lines 7402 along thefirst direction at a first edge (e.g., left edge) but do align at asecond edge (e.g., right edge) of the second version 7300D of the celltype along the second direction. In one such embodiment, the secondversion of the cell type 7300D is a second version of a NAND cell.

In another embodiment, the first and second versions are selected fromcell types 7300A and 7300B. Individual ones of the first plurality ofinterconnect lines of the first version 7300A of the cell type alignwith individual ones of the plurality of gate lines 7402 along the firstdirection at both edges of the first version of the cell type 7300Aalong the second direction. In one embodiment, the first version 7300Aof the cell type is a first version of an inverter cell. It is to beappreciated that individual ones of the second plurality of interconnectlines of the second version 7300B of the cell type would otherwise notalign with individual ones of the plurality of gate lines 7402 along thefirst direction at both edges of the second version 7300B of the celltype along the second direction. In one embodiment, the second version7300B of the cell type is a second version of an inverter cell.

FIG. 76 illustrates an exemplary unacceptable (fail) layout based onstandard cells having different versions, in accordance with anembodiment of the present disclosure. Referring to FIG. 76, a layout7600 includes three cells of the type 7300C/7300D as placed in orderfrom left to right between borders 7406 and 7408: 7300D, abutting first7300C and spaced apart second 7300C. The appropriate selection between7300C and 7300D is based on the alignment of the E or O designations onthe corresponding gate lines 7402, as is shown. However, the layout 7600also includes cells of the type 7300A/7300B as placed in order from leftto right below border 7408: first 7300A spaced apart from second 7300A.The layout 7600 differs from 7500 in that the second 7300A is moved oneline over to the left. Although, the selection between 7300A and 7300Bshould be based on the alignment of the E or O designations on thecorresponding gate lines 7402, it is not, and second cell 7300A ismisaligned, one consequence of which is misaligned power (p) lines.Layout 7600 is a fail cell since a dirty registration (DR) occurs in thelayout 7600.

FIG. 77 illustrates another exemplary acceptable (pass) layout based onstandard cells having different versions, in accordance with anembodiment of the present disclosure. Referring to FIG. 77, a layout7700 includes three cells of the type 7300C/7300D as placed in orderfrom left to right between borders 7406 and 7408: 7300D, abutting first7300C and spaced apart second 7300C. The selection between 7300C and7300D is based on the alignment of the E or O designations on thecorresponding gate lines 7402. The layout 7700 also includes cells ofthe type 7300A/7300B as placed in order from left to right below border7408: 7300A spaced apart from 7300B. The position of 7300B is the sameas the position of 7300A in the layout 7600, but the selected cell 7300Bis based on the appropriate alignment of the O designation on thecorresponding gate lines 7402. Layout 7700 is a pass cell in the sensethat no dirty registration (DR) occurs in the layout 7700. It is to beappreciated that p designates power, and a, b, c or o are exemplarypins. In the arrangement 7700 the power lines p line up with one anotheracross border 7408.

Referring collectively to FIGS. 76 and 77, a method of fabricating alayout for an integrated circuit structure includes designatingalternating ones of a plurality of gate lines 7402 parallel along afirst direction as even (E) or odd (O) along a second direction. Alocation is then selected for a cell type over the plurality of gatelines 7402. The method also includes selecting between a first versionof the cell type and a second version of the cell type depending on thelocation, the second version structurally different than the firstversion, wherein the selected version of the cell type has an even (E)or odd (O) designation for interconnects at edges of the cell type alongthe second direction, and wherein the designation of the edges of thecell type match with the designation of individual ones of the pluralityof gate lines below the interconnects.

In another aspect, one or more embodiments are directed to thefabrication of metal resistors on a fin-based structure included in afin field effect transistor (FET) architecture. In an embodiment, suchprecision resistors are implanted as a fundamental component of asystem-on-chip (SoC) technology, due to the high speed IOs required forfaster data transfer rates. Such resistors may enable the realization ofhigh speed analog circuitry (such as CSI/SERDES) and scaled IOarchitectures due to the characteristics of having low variation andnear-zero temperature coefficients. In one embodiment, a resistordescribed herein is a tunable resistor.

To provide context, traditional resistors used in current processtechnologies typically fall in one of two classes: general resistors orprecision resistors. General resistors, such as trench contactresistors, are cost-neutral but may suffer from high variation due tovariations inherent in the fabrication methods utilized or theassociated large temperature coefficients of the resistors, or both.Precision resistors may alleviate the variation and temperaturecoefficient issues, but often at the expense of higher process cost andan increased number of fabrication operations required. The integrationof polysilicon precision resistors is proving increasingly difficult inhigh-k/metal gate process technologies.

In accordance with embodiments, fin-based thin film resistors (TFRs) aredescribed. In one embodiment, such resistors have a near-zerotemperature coefficient. In one embodiment, such resistors exhibitreduced variation from dimensional control. In accordance with one ormore embodiments of the present disclosure, an integrated precisionresistor is fabricated within a fin-FET transistor architecture. It isto be appreciated that traditional resistors used in high-k/metal gateprocess technologies are typically tungsten trench contacts (TCN), wellresistors, or polysilicon precision resistors. Such resistors either addprocess cost or complexity, or suffer from high variation and poortemperature coefficients due to variations in the fabrication processesused. By contrast, in an embodiment, fabrication of a fin-integratedthin film resistor enables a cost-neutral, good (close to zero)temperature coefficient, and low variation alternative to knownapproaches.

To provide further context, state-of-the-art precision resistors havebeen fabricated using two-dimensional (2D) metallic thin films or highlydoped poly lines. Such resistors tend to be discretized into templatesof fixed values and, hence, a finer granularity of resistance values ishard to achieve.

Addressing one or more of the above issues, in accordance with one ormore embodiments of the present disclosure, design of a high densityprecision resistor using a fin backbone, such as a silicon fin backbone,is described herein. In one embodiment, advantages of such a highdensity precision resistor include that the high density can be achievedby using fin packing density. Additionally, in one embodiment, such aresistor is integrated on the same level as active transistors, leadingto the fabrication of compact circuitry. The use of a silicon finbackbone may permit high packing density and provide multiple degrees offreedom to control the resistance of the resistor. Accordingly, in aspecific embodiment, the flexibility of a fin patterning process isleveraged to provide a wide range of resistance values, resulting intunable precision resistor fabrication.

As an exemplary geometry for a fin-based precision resistor, FIG. 78illustrates a partially cut plan view and a correspondingcross-sectional view of a fin-based thin film resistor structure, wherethe cross-sectional view is taken along the a-a′ axis of the partiallycut plan view, in accordance with an embodiment of the presentdisclosure.

Referring to FIG. 78, an integrated circuit structure 7800 includes asemiconductor fin 7802 protruding through a trench isolation region 7814above a substrate 7804. In one embodiment, the semiconductor fin 7802protrudes from and is continuous with the substrate 7804, as isdepicted. The semiconductor fin has a top surface 7805, a first end 7806(shown as a dashed line in the partially cut plan view since the fin iscovered in this view), a second end 7808 (shown as a dashed line in thepartially cut plan view since the fin is covered in this view), and apair of sidewalls 7807 between the first end 7806 and the second end7808. It is to be appreciated that the sidewalls 7807 are actuallycovered by layer 7812 in the partially cut plan view).

An isolation layer 7812 is conformal with the top surface 7805, thefirst end 7806, the second end 7808, and the pair of sidewalls 7807 ofthe semiconductor fin 7802. A metal resistor layer 7810 is conformalwith the isolation layer 7814 conformal with the top surface 7805 (metalresistor layer portion 7810A), the first end 7806 (metal resistor layerportion 7810B), the second end 7808 (metal resistor layer portion7810C), and the pair of sidewalls 7807 (metal resistor layer portions7810D) of the semiconductor fin 7802. In a particular embodiment, themetal resistor layer 7810 includes a footed feature 7810E adjacent tothe sidewalls 7807, as is depicted. The isolation layer 7812electrically isolates the metal resistor layer 7810 from thesemiconductor fin 7802 and, hence, from the substrate 7804.

In an embodiment, the metal resistor layer 7810 is composed of amaterial suitable to provide a near-zero temperature coefficient, inthat the resistance of the metal resistor layer portion 7810 does notchange significantly over a range of operating temperatures of a thinfilm resistor (TFR) fabricated therefrom. In an embodiment, the metalresistor layer 7810 is a titanium nitride (TiN) layer. In anotherembodiment, the metal resistor layer 7810 is a tungsten (W) metal layer.It is to be appreciated that other metals may be used for the metalresistor layer 7810 in place of, or in combination with, titaniumnitride (TiN) or tungsten (W). In an embodiment, the metal resistorlayer 7810 has a thickness approximately in the range of 2-5 nanometers.In an embodiment, the metal resistor layer 7810 has a resistivityapproximately in the range of 100-100,000 ohms/square.

In an embodiment, an anode electrode and a cathode electrode areelectrically connected to the metal resistor layer 7810, exemplaryembodiments of which are described in greater detail below inassociation with FIG. 84. In one such embodiment, the metal resistorlayer 7810, the anode electrode, and the cathode electrode form aprecision thin film resistor (TFR) passive device. In an embodiment, theTFR based on the structure 7800 of FIG. 78 permits precise control ofresistance based on fin 7802 height, fin 7802 width, metal resistorlayer 7810 thickness and total fin 7802 length. These degrees of freedommay allow a circuit designer to achieve a selected resistance value.Additionally, since the resistor patterning is fin-based, high densityis possible at on the scale of transistor density.

In an embodiment, state-of-the-art finFET processing operations are usedto provide a fin suitable for fabricating a fin-based resistor. Anadvantage of such an approach may lie in its high density and proximityto the active transistors, enabling ease of integration into circuits.Also, the flexibility in the geometry of the underlying fin allows for awide range of resistance values. In an exemplary processing scheme, afin is first patterned using backbone lithography and spacerizationapproach. The fin is then covered with isolation oxide which is recessedto set the height of the resistor. An insulating oxide is then depositedconformally on the fin to separate the conductive film from theunderlying substrate, such as an underlying silicon substrate. A metalor highly doped polysilicon film is then deposited on the fin. The filmis then spacerized to create the precision resistor.

In an exemplary processing scheme, FIGS. 79-83 illustrate plan views andcorresponding cross-sectional view representing various operations in amethod of fabricating a fin-based thin film resistor structure, inaccordance with an embodiment of the present disclosure.

Referring to FIG. 79, a plan view and corresponding cross-sectional viewtaken along the b-b′ axis of the plan view illustrate a stage of aprocess flow following forming of a backbone template structure 7902 ona semiconductor substrate 7801. A sidewall spacer layer 7904 is thenformed conformal with sidewall surfaces of the backbone templatestructure 7902. In an embodiment, following patterning of the backbonetemplate structure 7902, conformal oxide material is deposited and thenanisotropically etched (spacerized) to provide the sidewall spacer layer7904.

Referring to FIG. 80, a plan view illustrates a stage of the processflow following exposure of a region 7906 of the sidewall spacer layer7904, e.g., by a lithographic masking and exposure process. The portionsof the sidewall spacer layer 7904 included in region 7906 are thenremoved, e.g., by an etch process. The portions removed are thoseportions that will be used for ultimate fin definition.

Referring to FIG. 81, a plan view and corresponding cross-sectional viewtaken along the c-c′ axis of the plan view illustrate a stage of theprocess flow following removal of the portions of the sidewall spacerlayer 7904 included in region 7906 of FIG. 80 to form a fin patterningmask (e.g., oxide fin patterning mask). The backbone template structure7902 is then removed and the remaining patterning mask is used as anetch mask to pattern the substrate 7801. Upon patterning of thesubstrate 7801 and subsequent removal of the fin patterning mask, asemiconductor fin 7802 remains protruding from and continuous with a nowpatterned semiconductor substrate 7804. The semiconductor fin 7802 has atop surface 7805, a first end 7806, a second end 7808, and a pair ofsidewalls 7807 between the first end and the second end, as describedabove in association with FIG. 78.

Referring to FIG. 82, a plan view and corresponding cross-sectional viewtaken along the d-d′ axis of the plan view illustrate a stage of theprocess flow following formation of a trench isolation layer 7814. In anembodiment, the trench isolation layer 7814 is formed by depositing ofan insulating material and subsequent recessing to define the fin height(Hsi) to define fin height.

Referring to FIG. 83, a plan view and corresponding cross-sectional viewtaken along the e-e′ axis of the plan view illustrate a stage of theprocess flow following formation of an isolation layer 7812. In anembodiment, the isolation layer 7812 is formed by a chemical vapordeposition (CVD) process. The isolation layer 7812 is formed conformalwith the top surface (7805), the first end 7806, the second end 7808,and the pair of sidewalls (7807) of the semiconductor fin 7802. A metalresistor layer 7810 is then formed conformal with the isolation layer7812 conformal with the top surface, the first end, the second end, andthe pair of sidewalls of the semiconductor fin 7802.

In an embodiment, the metal resistor layer 7810 is formed using ablanket deposition and subsequent anisotropic etching process. In anembodiment, the metal resistor layer 7810 is formed using atomic layerdeposition (ALD). In an embodiment, the metal resistor layer 7810 isformed to a thickness in the range of 2-5 nanometers. In an embodiment,the metal resistor layer 7810 is or includes a titanium nitride (TiN)layer or a tungsten (W) layer. In an embodiment, the metal resistorlayer 7810 is formed to have a resistivity in the range of 100-100,000ohms/square.

In a subsequent processing operation, a pair of anode or cathodeelectrodes may be formed and may be electrically connected to the metalresistor layer 7810 of the structure of FIG. 83. As an example, FIG. 84illustrates a plan view of a fin-based thin film resistor structure witha variety of exemplary locations for anode or cathode electrodecontacts, in accordance with an embodiment of the present disclosure.

Referring to FIG. 84, a first anode or cathode electrode, e.g., one of8400, 8402, 8404, 8406, 8408, 8410, is electrically connected to themetal resistor layer 7810. A second anode or cathode electrode, e.g.,another of 8400, 8402, 8404, 8406, 8408, 8410, is electrically connectedto the metal resistor layer 7810. In an embodiment, the metal resistorlayer 7810, the anode electrode, and the cathode electrode form aprecision thin film resistor (TFR) passive device. The precision TFRpassive device may be tunable in that the resistance can be selectedbased on the distance between the first anode or cathode electrode andthe second anode or cathode electrode. The options may be provided byforming a variety of actual electrodes, e.g., 8400, 8402, 8404, 8406,8408, 8410 and other possibilities, and then selecting the actualpairing based on interconnecting circuitry. Alternatively, a singleanode or cathode pairing may be formed, with the locations for eachselected during fabrication of the TFR device. In either case, in anembodiment, the location for one of the anode or cathode electrodes isat an end of the fin 7802 (e.g., at location 8400 or 8402), is at acorner of the fin 7802 (e.g., at location 8404, 8406 or 8408), or in acenter of a transition between corners (e.g., at location 8410).

In an exemplary embodiment, the first anode or cathode electrode iselectrically connected to the metal resistor layer 7810 proximate to thefirst end 7806, e.g., at location 8400, of the semiconductor fin 7802.The second anode or cathode electrode is electrically connected to themetal resistor layer 7810 proximate to the second end 7808, e.g., atlocation 8402, of the semiconductor fin 7802.

In another exemplary embodiment, the first anode or cathode electrode iselectrically connected to the metal resistor layer 7810 proximate to thefirst end 7806, e.g., at location 8400, of the semiconductor fin 7802.The second anode or cathode electrode is electrically connected to themetal resistor layer 7810 distal from the second end 7808, e.g., atlocation 8410, 8408, 8406 or 8404, of the semiconductor fin 7802.

In another exemplary embodiment, the first anode or cathode electrode iselectrically connected to the metal resistor layer 7810 distal from thefirst end 7806, e.g., at location 8404 or 8406, of the semiconductor fin7802. The second anode or cathode electrode is electrically connected tothe metal resistor layer 7810 distal from the second end 7808, e.g., atlocation 8410 or 8408, of the semiconductor fin 7802.

More specifically, in accordance with one or more embodiments of thepresent disclosure, a topographical feature of a fin-based transistorarchitecture is used as a foundation for fabricating an embeddedresistor. In one embodiment, a precision resistor is fabricated on a finstructure. In a specific embodiment, such an approach enables very highdensity integration of a passive component such as a precision resistor.

It is to be appreciated that a variety of fin geometries are suitablefor fabricating a fin-based precision resistor. FIGS. 85A-85D illustrateplan views of various fin geometries for fabricating a fin-basedprecision resistor, in accordance with an embodiment of the presentdisclosure.

In an embodiment, referring to FIGS. 85A-85C, a semiconductor fin 7802is a non-linear semiconductor fin. In one embodiment, the semiconductorfin 7802 protrudes through a trench isolation region above a substrate.A metal resistor layer 7810 is conformal with an isolation layer (notshown) conformal with the non-linear semiconductor fin 7802. In oneembodiment, two or more anode or cathode electrodes 8400 areelectrically connected to the metal resistor layer 7810, with exemplaryoptional locations shown by the dashed circles in FIGS. 85A-85C.

A non-linear fin geometry includes one or more corners, such as, but notlimited to, a single corner (e.g., L-shaped), two corners (e.g.,U-shaped), four corners (e.g., S-shaped), or six corners (e.g., thestructure of FIG. 78). In an embodiment, the non-linear fin geometry isan open structure geometry. In another embodiment, the non-linear fingeometry is a closed structure geometry.

As exemplary embodiments of an open structure geometry for a non-linearfin geometry, FIG. 85A illustrates a non-linear fin having one corner toprovide an open structure L-shaped geometry. FIG. 85B illustrates anon-linear fin having two corners to provide an open structure U-shapedgeometry. In the case of an open structure, the non-linear semiconductorfin 7802 has a top surface, a first end, a second end, and a pair ofsidewalls between the first end and the second end. A metal resistorlayer 7810 is conformal with an isolation layer (not shown) conformalwith the top surface, the first end, the second end, and the pair ofsidewalls between the first end and the second end.

In a specific embodiment, referring again to FIGS. 85A and 85B, a firstanode or cathode electrode is electrically connected to the metalresistor layer 7810 proximate to a first end of an open structurenon-linear semiconductor fin, and a second anode or cathode electrode iselectrically connected to the metal resistor layer 7810 proximate to asecond end of the open structure non-linear semiconductor fin. Inanother specific embodiment, a first anode or cathode electrode iselectrically connected to the metal resistor layer 7810 proximate to afirst end of an open structure non-linear semiconductor fin, and asecond anode or cathode electrode is electrically connected to the metalresistor layer 7810 distal from a second end of the open structurenon-linear semiconductor fin. In another specific embodiment, a firstanode or cathode electrode is electrically connected to the metalresistor layer 7810 distal from a first end of an open structurenon-linear semiconductor fin, and a second anode or cathode electrode iselectrically connected to the metal resistor layer 7810 distal from asecond end of the open structure non-linear semiconductor fin.

As an exemplary embodiment of a closed structure geometry for anon-linear fin geometry, FIG. 85C illustrates a non-linear fin havingfour corners to provide a closed structure square-shaped orrectangular-shaped geometry. In the case of a closed structure, thenon-linear semiconductor fin 7802 has a top surface and a pair ofsidewalls and, in particular, an inner sidewall and an outer sidewall.However, the closed structure does not include exposed first and secondends. A metal resistor layer 7810 is conformal with an isolation layer(not shown) conformal with the top surface, the inner sidewall, and theouter sidewall of the fin 7802.

In another embodiment, referring to FIG. 85D, a semiconductor fin 7802is a linear semiconductor fin. In one embodiment, the semiconductor fin7802 protrudes through a trench isolation region above a substrate. Ametal resistor layer 7810 is conformal with an isolation layer (notshown) conformal with the linear semiconductor fin 7802. In oneembodiment, two or more anode or cathode electrodes 8400 areelectrically connected to the metal resistor layer 7810, with exemplaryoptional locations shown by the dashed circles in FIG. 85D.

In another aspect, in accordance with an embodiment of the presentdisclosure, new structures for high resolution phase shift masks (PSM)fabrication for lithography are described. Such PSM masks may be usedfor general (direct) lithography or complementary lithography.

Photolithography is commonly used in a manufacturing process to formpatterns in a layer of photoresist. In the photolithography process, aphotoresist layer is deposited over an underlying layer that is to beetched. Typically, the underlying layer is a semiconductor layer, butmay be any type of hardmask or dielectric material. The photoresistlayer is then selectively exposed to radiation through a photomask orreticle. The photoresist is then developed and those portions of thephotoresist that are exposed to the radiation are removed, in the caseof “positive” photoresist.

The photomask or reticle used to pattern the wafer is placed within aphotolithography exposure tool, commonly known as a “stepper” or“scanner.” In the stepper or scanner machine, the photomask or reticleis placed between a radiation source and a wafer. The photomask orreticle is typically formed from patterned chrome (absorber layer)placed on a quartz substrate. The radiation passes substantiallyunattenuated through the quartz sections of the photomask or reticle inlocations where there is no chrome. In contrast, the radiation does notpass through the chrome portions of the mask. Because radiation incidenton the mask either completely passes through the quartz sections or iscompletely blocked by the chrome sections, this type of mask is referredto as a binary mask. After the radiation selectively passes through themask, the pattern on the mask is transferred into the photoresist byprojecting an image of the mask into the photoresist through a series oflenses.

As features on the photomask or reticle become closer and closertogether, diffraction effects begin to take effect when the size of thefeatures on the mask are comparable to the wavelength of the lightsource. Diffraction blurs the image projected onto the photoresist,resulting in poor resolution.

One approach for preventing diffraction patterns from interfering withthe desired patterning of the photoresist is to cover selected openingsin the photomask or reticle with a transparent layer known as a shifter.The shifter shifts one of the sets of exposing rays out of phase withanother adjacent set, which nullifies the interference pattern fromdiffraction. This approach is referred to as a phase shift mask (PSM)approach. Nevertheless, alternative mask fabrication schemes that reducedefects and increase throughput in mask production are important focusareas of lithography process development.

One or more embodiments of the present disclosure are directed tomethods for fabricating lithographic masks and the resultinglithographic masks. To provide context, the requirement to meetaggressive device scaling goals set forth by the semiconductor industryharbors on the ability of lithographic masks to pattern smaller featureswith high fidelity. However, approaches to pattern smaller and smallerfeatures present formidable challenges for mask fabrication. In thisregard, lithographic masks widely in use today rely on the concept ofphase shift mask (PSM) technology to pattern features. However, reducingdefects while creating smaller and smaller patterns remains one of thebiggest obstacles in mask fabrication. Use of the phase shift mask mayhave several disadvantages. First, the design of a phase shift mask is arelatively complicated procedure that requires significant resources.Second, because of the nature of a phase shift mask, it is difficult tocheck whether or not defects are present in the phase shift mask. Suchdefects in phase shift masks arise out of the current integrationschemes employed to produce the mask itself. Some phase shift masksadopt a cumbersome and somewhat defect prone approach to pattern thicklight absorbing materials and then transfer the pattern to a secondarylayer that aids in the phase shifting. To complicate matters, theabsorber layer is subjected to plasma etch twice and, consequently,unwanted effects of plasma etch such as loading effects, reactive ionetch lag, charging and reproducible effects leads to defects in maskproduction.

Innovation in materials and novel integration techniques to fabricatedefect free lithographic masks remains a high priority to enable devicescaling. Accordingly, in order to exploit the full benefits of a phaseshift mask technology, a novel integration scheme that employs (i)patterning a shifter layer with high fidelity and (ii) patterning anabsorber only once and during the final stages of fabrication may beneeded. Additionally, such a fabrication scheme may also offer otheradvantages such as flexibility in material choices, decreased substratedamage during fabrication, and increased throughput in mask fabrication.

FIG. 86 illustrates a cross sectional view of a lithography maskstructure 8601 in accordance with an embodiment of the presentdisclosure. The lithography mask 8601 includes an in-die region 8610, aframe region 8620 and a die-frame interface region 8630. The die-frameinterface region 8630 includes adjacent portions of the in-die region8610 and the frame region 8620. The in-die region 8610 includes apatterned shifter layer 8606 disposed directly on a substrate 8600,wherein the patterned shifter layer has features that have sidewalls.The frame region 8620 surrounds the in-die region 8610 and includes apatterned absorber layer 8602 disposed directly on the substrate 8600.

The die-frame interface region 8630, disposed on substrate 8600,includes a dual layer stack 8640. The dual layer stack 8640 includes anupper layer 8604, disposed on the lower patterned shifter layer 8606.The upper layer 8604 of the dual layer stack 8640 is composed of a samematerial as the patterned absorber layer 8602 of the frame region 8620.

In an embodiment, an uppermost surface 8608 of the features of thepatterned shifter layer 8606 have a height that is different than anuppermost surface 8612 of features of the die-frame interface region anddifferent than an uppermost surface 8614 of the features in the frameregion. Furthermore, in an embodiment the height of the uppermostsurface 8612 of the features of the die-frame interface region isdifferent than the height of the uppermost surface 8614 of the featuresof the frame region. Typical thickness of the phase shifter layer 8606ranges from 40-100 nm, while a typical thickness of the absorber layerranges from 30-100 nm. In an embodiment, the thickness of the absorberlayer 8602 in the frame region 8620 is 50 nm, the combined thickness ofthe absorber layer 8604 which is disposed on the shifter layer 8606 inthe die-frame interface region 8630 is 120 nm and the thickness of theabsorber in the frame region is 70 nm. In an embodiment, the substrate8600 is quartz, the patterned shifter layer includes a material such asbut not limited to molybdenum-silicide, molybdenum-silicon oxynitride,molybdenum-silicon nitride, silicon oxynitride, or silicon nitride, andthe absorber material is chrome.

Embodiments disclosed herein may be used to manufacture a wide varietyof different types of integrated circuits or microelectronic devices.Examples of such integrated circuits include, but are not limited to,processors, chipset components, graphics processors, digital signalprocessors, micro-controllers, and the like. In other embodiments,semiconductor memory may be manufactured. Moreover, the integratedcircuits or other microelectronic devices may be used in a wide varietyof electronic devices known in the arts. For example, in computersystems (e.g., desktop, laptop, server), cellular phones, personalelectronics, etc. The integrated circuits may be coupled with a bus andother components in the systems. For example, a processor may be coupledby one or more buses to a memory, a chipset, etc. Each of the processor,the memory, and the chipset, may potentially be manufactured using theapproaches disclosed herein.

FIG. 87 illustrates a computing device 8700 in accordance with oneimplementation of the disclosure. The computing device 8700 houses aboard 8702. The board 8702 may include a number of components, includingbut not limited to a processor 7904 and at least one communication chip8706. The processor 8704 is physically and electrically coupled to theboard 8702. In some implementations the at least one communication chip8706 is also physically and electrically coupled to the board 8702. Infurther implementations, the communication chip 8706 is part of theprocessor 8704.

Depending on its applications, computing device 8700 may include othercomponents that may or may not be physically and electrically coupled tothe board 8702. These other components include, but are not limited to,volatile memory (e.g., DRAM), non-volatile memory (e.g., ROM), flashmemory, a graphics processor, a digital signal processor, a cryptoprocessor, a chipset, an antenna, a display, a touchscreen display, atouchscreen controller, a battery, an audio codec, a video codec, apower amplifier, a global positioning system (GPS) device, a compass, anaccelerometer, a gyroscope, a speaker, a camera, and a mass storagedevice (such as hard disk drive, compact disk (CD), digital versatiledisk (DVD), and so forth).

The communication chip 8706 enables wireless communications for thetransfer of data to and from the computing device 8700. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication chip 8706 may implementany of a number of wireless standards or protocols, including but notlimited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE,GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The computing device 8700 may include a plurality ofcommunication chips 8706. For instance, a first communication chip 8706may be dedicated to shorter range wireless communications such as Wi-Fiand Bluetooth and a second communication chip 8706 may be dedicated tolonger range wireless communications such as GPS, EDGE, GPRS, CDMA,WiMAX, LTE, Ev-DO, and others.

The processor 8704 of the computing device 8700 includes an integratedcircuit die packaged within the processor 8704. In some implementationsof embodiments of the disclosure, the integrated circuit die of theprocessor includes one or more structures, such as integrated circuitstructures built in accordance with implementations of the disclosure.The term “processor” may refer to any device or portion of a device thatprocesses electronic data from registers or memory to transform thatelectronic data, or both, into other electronic data that may be storedin registers or memory, or both.

The communication chip 8706 also includes an integrated circuit diepackaged within the communication chip 8706. In accordance with anotherimplementation of the disclosure, the integrated circuit die of thecommunication chip is built in accordance with implementations of thedisclosure.

In further implementations, another component housed within thecomputing device 8700 may contain an integrated circuit die built inaccordance with implementations of embodiments of the disclosure.

In various embodiments, the computing device 8700 may be a laptop, anetbook, a notebook, an ultrabook, a smartphone, a tablet, a personaldigital assistant (PDA), an ultramobile PC, a mobile phone, a desktopcomputer, a server, a printer, a scanner, a monitor, a set-top box, anentertainment control unit, a digital camera, a portable music player,or a digital video recorder. In further implementations, the computingdevice 8700 may be any other electronic device that processes data.

FIG. 88 illustrates an interposer 8800 that includes one or moreembodiments of the disclosure. The interposer 8800 is an interveningsubstrate used to bridge a first substrate 8802 to a second substrate8804. The first substrate 8802 may be, for instance, an integratedcircuit die. The second substrate 8804 may be, for instance, a memorymodule, a computer motherboard, or another integrated circuit die.Generally, the purpose of an interposer 8800 is to spread a connectionto a wider pitch or to reroute a connection to a different connection.For example, an interposer 8800 may couple an integrated circuit die toa ball grid array (BGA) 8806 that can subsequently be coupled to thesecond substrate 8804. In some embodiments, the first and secondsubstrates 8802/8804 are attached to opposing sides of the interposer8800. In other embodiments, the first and second substrates 8802/8804are attached to the same side of the interposer 8800. And in furtherembodiments, three or more substrates are interconnected by way of theinterposer 8800.

The interposer 8800 may be formed of an epoxy resin, afiberglass-reinforced epoxy resin, a ceramic material, or a polymermaterial such as polyimide. In further implementations, the interposermay be formed of alternate rigid or flexible materials that may includethe same materials described above for use in a semiconductor substrate,such as silicon, germanium, and other group III-V and group IVmaterials.

The interposer may include metal interconnects 8808 and vias 8810,including but not limited to through-silicon vias (TSVs) 8812. Theinterposer 8800 may further include embedded devices 8814, includingboth passive and active devices. Such devices include, but are notlimited to, capacitors, decoupling capacitors, resistors, inductors,fuses, diodes, transformers, sensors, and electrostatic discharge (ESD)devices. More complex devices such as radio-frequency (RF) devices,power amplifiers, power management devices, antennas, arrays, sensors,and MEMS devices may also be formed on the interposer 8000. Inaccordance with embodiments of the disclosure, apparatuses or processesdisclosed herein may be used in the fabrication of interposer 8800 or inthe fabrication of components included in the interposer 8800.

FIG. 89 is an isometric view of a mobile computing platform 8900employing an integrated circuit (IC) fabricated according to one or moreprocesses described herein or including one or more features describedherein, in accordance with an embodiment of the present disclosure.

The mobile computing platform 8900 may be any portable device configuredfor each of electronic data display, electronic data processing, andwireless electronic data transmission. For example, mobile computingplatform 8900 may be any of a tablet, a smart phone, laptop computer,etc. and includes a display screen 8905 which in the exemplaryembodiment is a touchscreen (capacitive, inductive, resistive, etc.), achip-level (SoC) or package-level integrated system 8910, and a battery8913. As illustrated, the greater the level of integration in the system8910 enabled by higher transistor packing density, the greater theportion of the mobile computing platform 8900 that may be occupied bythe battery 8913 or non-volatile storage, such as a solid state drive,or the greater the transistor gate count for improved platformfunctionality. Similarly, the greater the carrier mobility of eachtransistor in the system 8910, the greater the functionality. As such,techniques described herein may enable performance and form factorimprovements in the mobile computing platform 8900.

The integrated system 8910 is further illustrated in the expanded view8920. In the exemplary embodiment, packaged device 8977 includes atleast one memory chip (e.g., RAM), or at least one processor chip (e.g.,a multi-core microprocessor and/or graphics processor) fabricatedaccording to one or more processes described herein or including one ormore features described herein. The packaged device 8977 is furthercoupled to the board 8960 along with one or more of a power managementintegrated circuit (PMIC) 8915, RF (wireless) integrated circuit (RFIC)8925 including a wideband RF (wireless) transmitter and/or receiver(e.g., including a digital baseband and an analog front end modulefurther comprises a power amplifier on a transmit path and a low noiseamplifier on a receive path), and a controller thereof 8911.Functionally, the PMIC 8915 performs battery power regulation, DC-to-DCconversion, etc., and so has an input coupled to the battery 8913 andwith an output providing a current supply to all the other functionalmodules. As further illustrated, in the exemplary embodiment, the RFIC8925 has an output coupled to an antenna to provide to implement any ofa number of wireless standards or protocols, including but not limitedto Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20,long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM,GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well as anyother wireless protocols that are designated as 3G, 4G, 5G, and beyond.In alternative implementations, each of these board-level modules may beintegrated onto separate ICs coupled to the package substrate of thepackaged device 8977 or within a single IC (SoC) coupled to the packagesubstrate of the packaged device 8977.

In another aspect, semiconductor packages are used for protecting anintegrated circuit (IC) chip or die, and also to provide the die with anelectrical interface to external circuitry. With the increasing demandfor smaller electronic devices, semiconductor packages are designed tobe even more compact and must support larger circuit density.Furthermore, the demand for higher performance devices results in a needfor an improved semiconductor package that enables a thin packagingprofile and low overall warpage compatible with subsequent assemblyprocessing.

In an embodiment, wire bonding to a ceramic or organic package substrateis used. In another embodiment, a C4 process is used to mount a die to aceramic or organic package substrate. In particular, C4 solder ballconnections can be implemented to provide flip chip interconnectionsbetween semiconductor devices and substrates. A flip chip or ControlledCollapse Chip Connection (C4) is a type of mounting used forsemiconductor devices, such as integrated circuit (IC) chips, MEMS orcomponents, which utilizes solder bumps instead of wire bonds. Thesolder bumps are deposited on the C4 pads, located on the top side ofthe substrate package. In order to mount the semiconductor device to thesubstrate, it is flipped over with the active side facing down on themounting area. The solder bumps are used to connect the semiconductordevice directly to the substrate.

FIG. 90 illustrates a cross-sectional view of a flip-chip mounted die,in accordance with an embodiment of the present disclosure.

Referring to FIG. 90, an apparatus 9000 includes a die 9002 such as anintegrated circuit (IC) fabricated according to one or more processesdescribed herein or including one or more features described herein, inaccordance with an embodiment of the present disclosure. The die 9002includes metallized pads 9004 thereon. A package substrate 9006, such asa ceramic or organic substrate, includes connections 9008 thereon. Thedie 9002 and package substrate 9006 are electrically connected by solderballs 9010 coupled to the metallized pads 9004 and the connections 9008.An underfill material 9012 surrounds the solder balls 9010.

Processing a flip chip may be similar to conventional IC fabrication,with a few additional operations. Near the end of the manufacturingprocess, the attachment pads are metalized to make them more receptiveto solder. This typically consists of several treatments. A small dot ofsolder is then deposited on each metalized pad. The chips are then cutout of the wafer as normal. To attach the flip chip into a circuit, thechip is inverted to bring the solder dots down onto connectors on theunderlying electronics or circuit board. The solder is then re-melted toproduce an electrical connection, typically using an ultrasonic oralternatively reflow solder process. This also leaves a small spacebetween the chip's circuitry and the underlying mounting. In most casesan electrically-insulating adhesive is then “underfilled” to provide astronger mechanical connection, provide a heat bridge, and to ensure thesolder joints are not stressed due to differential heating of the chipand the rest of the system.

In other embodiments, newer packaging and die-to-die interconnectapproaches, such as through silicon via (TSV) and silicon interposer,are implemented to fabricate high performance Multi-Chip Module (MCM)and System in Package (SiP) incorporating an integrated circuit (IC)fabricated according to one or more processes described herein orincluding one or more features described herein, in accordance with anembodiment of the present disclosure.

Thus, embodiments of the present disclosure include advanced integratedcircuit structure fabrication.

Although specific embodiments have been described above, theseembodiments are not intended to limit the scope of the presentdisclosure, even where only a single embodiment is described withrespect to a particular feature. Examples of features provided in thedisclosure are intended to be illustrative rather than restrictiveunless stated otherwise. The above description is intended to cover suchalternatives, modifications, and equivalents as would be apparent to aperson skilled in the art having the benefit of the present disclosure.

The scope of the present disclosure includes any feature or combinationof features disclosed herein (either explicitly or implicitly), or anygeneralization thereof, whether or not it mitigates any or all of theproblems addressed herein. Accordingly, new claims may be formulatedduring prosecution of the present application (or an applicationclaiming priority thereto) to any such combination of features. Inparticular, with reference to the appended claims, features fromdependent claims may be combined with those of the independent claimsand features from respective independent claims may be combined in anyappropriate manner and not merely in the specific combinationsenumerated in the appended claims.

The following examples pertain to further embodiments. The variousfeatures of the different embodiments may be variously combined withsome features included and others excluded to suit a variety ofdifferent applications.

Example Embodiment 1

An integrated circuit structure includes a fin comprising silicon, thefin having a top and sidewalls. A gate dielectric layer is over the topof the fin and laterally adjacent the sidewalls of the fin. An N-typegate electrode is over the gate dielectric layer over the top of the finand laterally adjacent the sidewalls of the fin, the N-type gateelectrode comprising a P-type metal layer on the gate dielectric layer,and an N-type metal layer on the P-type metal layer. A first N-typesource or drain region is adjacent a first side of the gate electrode. Asecond N-type source or drain region is adjacent a second side of thegate electrode, the second side opposite the first side.

Example Embodiment 2

The integrated circuit structure of example embodiment 1, wherein theP-type metal layer comprises titanium and nitrogen, and the N-type metallayer comprises titanium, aluminum, carbon and nitrogen.

Example Embodiment 3

The integrated circuit structure of example embodiment 1 or 2, whereinthe P-type metal layer has a thickness in the range of 2-4 Angstroms.

Example Embodiment 4

The integrated circuit structure of example embodiment 1, 2 or 3,wherein the N-type gate electrode further comprises a conductive fillmetal layer on the N-type metal layer.

Example Embodiment 5

The integrated circuit structure of example embodiment 4, wherein theconductive fill metal layer comprises tungsten.

Example Embodiment 6

The integrated circuit structure of example embodiment 5, wherein theconductive fill metal layer comprises 95 or greater atomic percenttungsten and 0.1 to 2 atomic percent fluorine.

Example Embodiment 7

An integrated circuit structure includes a first N-type device having avoltage threshold (VT), the first N-type device having a first gatedielectric layer, and a first N-type metal layer on the first gatedielectric layer. The integrated circuit structure also includes asecond N-type device has a voltage threshold (VT), the second N-typedevice having a second gate dielectric layer, a P-type metal layer onthe second gate dielectric layer, and a second N-type metal layer on theP-type metal layer.

Example Embodiment 8

The integrated circuit structure of example embodiment 7, wherein the VTof the second N-type device is higher than the VT of the first N-typedevice.

Example Embodiment 9

The integrated circuit structure of example embodiment 7 or 8, whereinthe first N-type metal layer and the second N-type metal layer have asame composition.

Example Embodiment 10

The integrated circuit structure of example embodiment 7 or 8, whereinthe first N-type metal layer and the second N-type metal layer have asame thickness.

Example Embodiment 11

The integrated circuit structure of example embodiment 10, wherein thefirst N-type metal layer and the second N-type metal layer have a samecomposition.

Example Embodiment 12

The integrated circuit structure of example embodiment 7, 8, 9, 10 or11, wherein the second N-type metal layer comprises titanium, aluminum,carbon and nitrogen, and the P-type metal layer comprises titanium andnitrogen.

Example Embodiment 13

The integrated circuit structure of example embodiment 7, 8, 9, 10, 11or 12, further comprising a third N-type device having a voltagethreshold (VT), the third N-type device having a third gate dielectriclayer, and a third N-type metal layer on the third gate dielectriclayer, wherein the VT of the third N-type device is different than theVT of the first N-type device.

Example Embodiment 14

The integrated circuit structure of example embodiment 13, wherein thefirst N-type device has a channel region having a dopant concentration,and the third N-type device has a channel region having a dopantconcentration, and wherein the dopant concentration of the channelregion of the first N-type device is different than the dopantconcentration of the channel region of the third N-type device.

Example Embodiment 15

The integrated circuit structure of example embodiment 13 or 14, whereinthe first N-type metal layer and the third N-type metal layer have asame composition.

Example Embodiment 16

The integrated circuit structure of example embodiment 13 or 14, whereinthe first N-type metal layer and the third N-type metal layer have asame thickness.

Example Embodiment 17

The integrated circuit structure of example embodiment 13 or 14, whereinthe first N-type metal layer and the third N-type metal layer have asame composition and have a same thickness.

Example Embodiment 18

An integrated circuit structure includes a first P-type device having avoltage threshold (VT), the first P-type device having a first gatedielectric layer, and a first P-type metal layer on the first gatedielectric layer, the first P-type metal layer having a thickness. Theintegrated circuit structure also includes a second P-type device has avoltage threshold (VT), the second P-type device having a second gatedielectric layer, and a second P-type metal layer on the second gatedielectric layer, wherein the second P-type metal layer has a thicknessgreater than the thickness of the first P-type metal layer.

Example Embodiment 19

The integrated circuit structure of example embodiment 18, wherein theVT of the second P-type device is lower than the VT of the first P-typedevice.

Example Embodiment 20

The integrated circuit structure of example embodiment 18 or 19, whereinthe first P-type metal layer and the second P-type metal layer have asame composition.

Example Embodiment 21

The integrated circuit structure of example embodiment 18, 19 or 20,wherein the first P-type metal layer and the second P-type metal layerboth comprise titanium and nitrogen.

Example Embodiment 22

The integrated circuit structure of example embodiment 18, 19, 20 or 21,wherein the thickness of the first P-type metal layer is less than awork-function saturation thickness of a material of the first P-typemetal layer.

Example Embodiment 23

The integrated circuit structure of example embodiment 18, 19, 20, 2 or22, wherein the second P-type metal layer comprises a first metal filmon a second metal film, and a seam between the first metal film and thesecond metal film.

Example Embodiment 24

The integrated circuit structure of example embodiment 18, 19, 20, 21,22 or 23, further comprising a third P-type device having a voltagethreshold (VT), the third P-type device having a third gate dielectriclayer, and a third P-type metal layer on the third gate dielectriclayer, wherein the VT of the third P-type device is different than theVT of the first P-type device, wherein the first P-type metal layer andthe third P-type metal layer have a same thickness.

Example Embodiment 25

The integrated circuit structure of example embodiment 24, wherein thefirst P-type device has a channel region having a dopant concentration,and the third P-type device has a channel region having a dopantconcentration, and wherein the dopant concentration of the channelregion of the first P-type device is different than the dopantconcentration of the channel region of the third P-type device.

Example Embodiment 26

The integrated circuit structure of example embodiment 24 or 25, whereinthe first P-type metal layer and the third P-type metal layer have asame composition.

Example Embodiment 27

The integrated circuit structure of example embodiment 18, furthercomprising a third P-type device having a voltage threshold (VT), thethird P-type device having a third gate dielectric layer, and a thirdP-type metal layer on the third gate dielectric layer, wherein the VT ofthe third P-type device is different than the VT of the second P-typedevice, wherein the second P-type metal layer and the third P-type metallayer have a same thickness.

Example Embodiment 28

The integrated circuit structure of example embodiment 27, wherein thesecond P-type device has a channel region having a dopant concentration,and the third P-type device has a channel region having a dopantconcentration, and wherein the dopant concentration of the channelregion of the second P-type device is different than the dopantconcentration of the channel region of the third P-type device.

Example Embodiment 29

The integrated circuit structure of example embodiment 27 or 28, whereinthe second P-type metal layer and the third P-type metal layer have asame composition.

Example Embodiment 30

An integrated circuit structure includes a first N-type device having afirst gate dielectric layer, and a first N-type metal layer on the firstgate dielectric layer. The integrated circuit structure also includes asecond N-type device having a second gate dielectric layer, a firstP-type metal layer on the second gate dielectric layer, and a secondN-type metal layer on the first P-type metal layer. The integratedcircuit structure also includes a first P-type device having a thirdgate dielectric layer, and a second P-type metal layer on the third gatedielectric layer, the second P-type metal layer having a thickness. Theintegrated circuit structure also includes a second P-type device havinga fourth gate dielectric layer, and a third P-type metal layer on thefourth gate dielectric layer, wherein the third P-type metal layer has athickness greater than the thickness of the second P-type metal layer.

Example Embodiment 31

The integrated circuit structure of example embodiment 30, wherein thefirst N-type device has a voltage threshold (VT), the second N-typedevice has a voltage threshold (VT), and the VT of the second N-typedevice is lower than the VT of the first N-type device.

Example Embodiment 32

The integrated circuit structure of example embodiment 30, wherein thefirst P-type device has a voltage threshold (VT), the second P-typedevice has a voltage threshold (VT), and the VT of the second P-typedevice is lower than the VT of the first P-type device.

Example Embodiment 33

The integrated circuit structure of example embodiment 32, wherein thefirst N-type device has a voltage threshold (VT), the second N-typedevice has a voltage threshold (VT), and the VT of the second N-typedevice is lower than the VT of the first N-type device.

Example Embodiment 34

The integrated circuit structure of example embodiment 30, 31, 32 or 33,wherein the third P-type metal layer comprises a first metal film on asecond metal film, and a seam between the first metal film and thesecond metal film.

Example Embodiment 35

The integrated circuit structure of example embodiment 30 31, 32, 33 or34, further comprising a third N-type device having a fifth gatedielectric layer, and a third N-type metal layer on the fifth gatedielectric layer, wherein the first N-type device has a channel regionhaving a dopant concentration, and the third N-type device has a channelregion having a dopant concentration, and wherein the dopantconcentration of the channel region of the first N-type device isdifferent than the dopant concentration of the channel region of thethird N-type device.

Example Embodiment 36

The integrated circuit structure of example embodiment 35, wherein thefirst N-type metal layer and the third N-type metal layer have a samecomposition and have a same thickness.

Example Embodiment 37

The integrated circuit structure of example embodiment 35 or 36, whereinthe first N-type device has a voltage threshold (VT), the second N-typedevice has a voltage threshold (VT), the third N-type device has avoltage threshold (VT), the VT of the second N-type device is lower thanthe VT of the first N-type device, and the VT of the third N-type deviceis different than the VT of the first N-type device and is differentthan the VT of the second N-type device.

Example Embodiment 38

The integrated circuit structure of example embodiment 30, 31, 32, 33 or34, further comprising a third P-type device having a fifth gatedielectric layer, and a fourth P-type metal layer on the fifth gatedielectric layer, wherein the second P-type metal layer and the fourthP-type metal layer have a same thickness, wherein the first P-typedevice has a channel region having a dopant concentration, and the thirdP-type device has a channel region having a dopant concentration, andwherein the dopant concentration of the channel region of the firstP-type device is different than the dopant concentration of the channelregion of the third P-type device.

Example Embodiment 39

The integrated circuit structure of example embodiment 38, wherein thesecond P-type metal layer and the fourth P-type metal layer have a samecomposition.

Example Embodiment 40

The integrated circuit structure of example embodiment 38 or 39, whereinthe first P-type device has a voltage threshold (VT), the second P-typedevice has a voltage threshold (VT), the third P-type device has avoltage threshold (VT), the VT of the second P-type device is lower thanthe VT of the first P-type device, and the VT of the third P-type deviceis different than the VT of the first P-type device and is differentthan the VT of the second P-type device.

Example Embodiment 41

The integrated circuit structure of example embodiment 38, 39 or 40,further comprising a third N-type device having a sixth gate dielectriclayer, and a third N-type metal layer on the sixth gate dielectriclayer, wherein the first N-type device has a channel region having adopant concentration, and the third N-type device has a channel regionhaving a dopant concentration, and wherein the dopant concentration ofthe channel region of the first N-type device is different than thedopant concentration of the channel region of the third N-type device.

Example Embodiment 42

The integrated circuit structure of example embodiment 41, wherein thefirst N-type device has a voltage threshold (VT), the second N-typedevice has a voltage threshold (VT), the third N-type device has avoltage threshold (VT), the VT of the second N-type device is lower thanthe VT of the first N-type device, and the VT of the third N-type deviceis different than the VT of the first N-type device and is differentthan the VT of the second N-type device.

Example Embodiment 43

The integrated circuit structure of example embodiment 30, 31, 32, 33 or34, further comprising a third P-type device having a fifth gatedielectric layer, and a fourth P-type metal layer on the fifth gatedielectric layer, wherein the third P-type metal layer and the fourthP-type metal layer have a same thickness, wherein the second P-typedevice has a channel region having a dopant concentration, and the thirdP-type device has a channel region having a dopant concentration, andwherein the dopant concentration of the channel region of the secondP-type device is different than the dopant concentration of the channelregion of the third P-type device.

Example Embodiment 44

The integrated circuit structure of example embodiment 43, wherein thethird P-type metal layer and the fourth P-type metal layer have a samecomposition.

Example Embodiment 45

The integrated circuit structure of example embodiment 43 or 44, whereinthe first P-type device has a voltage threshold (VT), the second P-typedevice has a voltage threshold (VT), the third P-type device has avoltage threshold (VT), the VT of the second P-type device is lower thanthe VT of the first P-type device, and the VT of the third P-type deviceis different than the VT of the first P-type device and is differentthan the VT of the second P-type device.

Example Embodiment 46

The integrated circuit structure of example embodiment 43, 44 or 45,further comprising a third N-type device having a sixth gate dielectriclayer, and a third N-type metal layer on the sixth gate dielectriclayer, wherein the first N-type device has a channel region having adopant concentration, and the third N-type device has a channel regionhaving a dopant concentration, and wherein the dopant concentration ofthe channel region of the first N-type device is different than thedopant concentration of the channel region of the third N-type device.

Example Embodiment 47

The integrated circuit structure of example embodiment 46, wherein thefirst N-type device has a voltage threshold (VT), the second N-typedevice has a voltage threshold (VT), the third N-type device has avoltage threshold (VT), the VT of the second N-type device is lower thanthe VT of the first N-type device, and the VT of the third N-type deviceis different than the VT of the first N-type device and is differentthan the VT of the second N-type device.

Example Embodiment 48

A method of fabricating an integrated circuit structure includes forminga gate dielectric layer over a first semiconductor fin and over a secondsemiconductor fin. The method also includes forming a first P-type metallayer on the gate dielectric layer over the first semiconductor fin andover the second semiconductor fin. The method also includes removing thefirst P-type metal layer from the gate dielectric layer over the firstsemiconductor fin, but retaining the first P-type metal layer on thegate dielectric layer over the second semiconductor fin. The method alsoincludes forming a second P-type metal layer on the gate dielectriclayer over the first semiconductor fin, and on the first P-type metallayer on the gate dielectric layer over the second semiconductor fin.The method also includes forming a first P-type device having a voltagethreshold (VT), the first P-type device comprising a gate electrodecomprising the second P-type metal layer on the gate dielectric layerover the first semiconductor fin. The method also includes forming asecond P-type device having a voltage threshold (VT), the second P-typedevice comprising a gate electrode comprising the second P-type metallayer on the first P-type metal layer on the gate dielectric layer overthe second semiconductor fin, wherein the VT of the second P-type deviceis lower than the VT of the first P-type device.

Example Embodiment 49

The method of example embodiment 48, wherein the first P-type metallayer and the second P-type metal layer have a same composition.

Example Embodiment 50

The method of example embodiment 48, wherein the first P-type metallayer and the second P-type metal layer have a same thickness.

Example Embodiment 51

The method of example embodiment 50, wherein the first P-type metallayer and the second P-type metal layer have a same composition.

Example Embodiment 52

The method of example embodiment 48, 49, 50 or 51, wherein the secondP-type device comprises a seam between the first P-type metal layer andthe second P-type metal layer.

Example Embodiment 53

The method of example embodiment 48, 49, 50, 51, 52 or 53, furthercomprising forming a conductive fill metal layer on the second P-typemetal layer.

Example Embodiment 54

The method of example embodiment 53, wherein forming the conductive fillmetal layer comprises forming a tungsten-containing film using atomiclayer deposition (ALD) with a tungsten hexafluoride (WF₆) precursor.

Example Embodiment 55

A method of fabricating an integrated circuit structure includes forminga gate dielectric layer over a first semiconductor fin and over a secondsemiconductor fin. The method also includes forming a P-type metal layeron the gate dielectric layer over the first semiconductor fin and overthe second semiconductor fin. The method also includes removing theP-type metal layer from the gate dielectric layer over the firstsemiconductor fin, but retaining the P-type metal layer on the gatedielectric layer over the second semiconductor fin. The method alsoincludes forming an N-type metal layer on the gate dielectric layer overthe first semiconductor fin, and on the P-type metal layer on the gatedielectric layer over the second semiconductor fin. The method alsoincludes forming a first N-type device having a voltage threshold (VT),the first N-type device comprising a gate electrode comprising theN-type metal layer on the gate dielectric layer over the firstsemiconductor fin. The method also includes forming a second N-typedevice having a voltage threshold (VT), the second N-type devicecomprising a gate electrode comprising the N-type metal layer on theP-type metal layer on the gate dielectric layer over the secondsemiconductor fin, wherein the VT of the second N-type device is lowerthan the VT of the first N-type device.

Example Embodiment 56

The method of example embodiment 55, further comprising forming aconductive fill metal layer on the N-type metal layer.

Example Embodiment 57

The method of example embodiment 56, wherein forming the conductive fillmetal layer comprises forming a tungsten-containing film using atomiclayer deposition (ALD) with a tungsten hexafluoride (WF₆) precursor.

What is claimed is:
 1. An integrated circuit structure, comprising: afin comprising silicon, the fin having a top and sidewalls; a gatedielectric layer over the top of the fin and laterally adjacent thesidewalls of the fin; an N-type gate electrode over the gate dielectriclayer over the top of the fin and laterally adjacent the sidewalls ofthe fin, the N-type gate electrode comprising a P-type metal layer onthe gate dielectric layer, and an N-type metal layer on the P-type metallayer; a first N-type source or drain region adjacent a first side ofthe gate electrode; and a second N-type source or drain region adjacenta second side of the gate electrode, the second side opposite the firstside.
 2. The integrated circuit structure of claim 1, wherein the P-typemetal layer comprises titanium and nitrogen, and the N-type metal layercomprises titanium, aluminum, carbon and nitrogen.
 3. The integratedcircuit structure of claim 1, wherein the P-type metal layer has athickness in the range of 2-4 Angstroms.
 4. The integrated circuitstructure of claim 1, wherein the N-type gate electrode furthercomprises a conductive fill metal layer on the N-type metal layer. 5.The integrated circuit structure of claim 4, wherein the conductive fillmetal layer comprises tungsten.
 6. The integrated circuit structure ofclaim 5, wherein the conductive fill metal layer comprises 95 or greateratomic percent tungsten and 0.1 to 2 atomic percent fluorine.
 7. Anintegrated circuit structure, comprising: a first N-type device having avoltage threshold (VT), the first N-type device having a first gatedielectric layer, and a first N-type metal layer on the first gatedielectric layer; and a second N-type device having a voltage threshold(VT), the second N-type device having a second gate dielectric layer, aP-type metal layer on the second gate dielectric layer, and a secondN-type metal layer on the P-type metal layer.
 8. The integrated circuitstructure of claim 7, wherein the VT of the second N-type device ishigher than the VT of the first N-type device.
 9. The integrated circuitstructure of claim 7, wherein the first N-type metal layer and thesecond N-type metal layer have a same composition.
 10. The integratedcircuit structure of claim 7, wherein the first N-type metal layer andthe second N-type metal layer have a same thickness.
 11. The integratedcircuit structure of claim 10, wherein the first N-type metal layer andthe second N-type metal layer have a same composition.
 12. Theintegrated circuit structure of claim 7, wherein the second N-type metallayer comprises titanium, aluminum, carbon and nitrogen, and the P-typemetal layer comprises titanium and nitrogen.
 13. The integrated circuitstructure of claim 7, further comprising: a third N-type device having avoltage threshold (VT), the third N-type device having a third gatedielectric layer, and a third N-type metal layer on the third gatedielectric layer, wherein the VT of the third N-type device is differentthan the VT of the first N-type device.
 14. The integrated circuitstructure of claim 13, wherein the first N-type device has a channelregion having a dopant concentration, and the third N-type device has achannel region having a dopant concentration, and wherein the dopantconcentration of the channel region of the first N-type device isdifferent than the dopant concentration of the channel region of thethird N-type device.
 15. The integrated circuit structure of claim 13,wherein the first N-type metal layer and the third N-type metal layerhave a same composition.
 16. The integrated circuit structure of claim13, wherein the first N-type metal layer and the third N-type metallayer have a same thickness.
 17. The integrated circuit structure ofclaim 13, wherein the first N-type metal layer and the third N-typemetal layer have a same composition and have a same thickness.
 18. Anintegrated circuit structure, comprising: a first P-type device having avoltage threshold (VT), the first P-type device having a first gatedielectric layer, and a first P-type metal layer on the first gatedielectric layer, the first P-type metal layer having a thickness; and asecond P-type device having a voltage threshold (VT), the second P-typedevice having a second gate dielectric layer, and a second P-type metallayer on the second gate dielectric layer, wherein the second P-typemetal layer has a thickness greater than the thickness of the firstP-type metal layer.
 19. The integrated circuit structure of claim 18,wherein the VT of the second P-type device is lower than the VT of thefirst P-type device.
 20. The integrated circuit structure of claim 18,wherein the first P-type metal layer and the second P-type metal layerhave a same composition.
 21. The integrated circuit structure of claim18, wherein the first P-type metal layer and the second P-type metallayer both comprise titanium and nitrogen.
 22. The integrated circuitstructure of claim 18, wherein the thickness of the first P-type metallayer is less than a work-function saturation thickness of a material ofthe first P-type metal layer.
 23. The integrated circuit structure ofclaim 18, wherein the second P-type metal layer comprises a first metalfilm on a second metal film, and a seam between the first metal film andthe second metal film.
 24. The integrated circuit structure of claim 18,further comprising: a third P-type device having a voltage threshold(VT), the third P-type device having a third gate dielectric layer, anda third P-type metal layer on the third gate dielectric layer, whereinthe VT of the third P-type device is different than the VT of the firstP-type device, wherein the first P-type metal layer and the third P-typemetal layer have a same thickness.
 25. The integrated circuit structureof claim 24, wherein the first P-type device has a channel region havinga dopant concentration, and the third P-type device has a channel regionhaving a dopant concentration, and wherein the dopant concentration ofthe channel region of the first P-type device is different than thedopant concentration of the channel region of the third P-type device.